Luminous Landscape Forum
Raw & Post Processing, Printing => Printing: Printers, Papers and Inks => Topic started by: Robert Ardill on September 19, 2014, 08:47:20 am
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Hi,
I would really appreciate some advice as I'm thinking of selling my 24" HP Z3100 and replacing it with a Canon iPF6400 (without the internal disk and spectrophotometer as I can't afford these and already have an i1Pro2). I'm not considering the Epson 7900 because I've had two Epson printers (4000 and 4800) and I can't stand the thought of fighting through print head clogs again.
I would particularly appreciate comments from anyone who has had both the Z3100 and iPF6400 (or the Z3200 & iPF6450 / iPF8400 ...).
Here are some of my questions:
- Calibration: on the Z3100 every paper needs to be calibrated. From the reviews I've read it seems that the iPF6400 only needs to be calibrated with one paper and not for every individual paper. Is that true?
- Calibration: Does the densitometer give good calibration, or is it really necessary to have the built-in spectro?
- Head clogging: my Z3100 has shown zero problems over six years. Is the iPF6400 as good in this respect in your experience?
- Ink usage: how do the two printers compare? I've found the Z3100 to be excellent in the respect.
- Paper load: is the paper load (especially sheet paper) better than the pretty poor paper load on the Z3100?
- Printer noise: the specs show the iPF6400 at about 35dB when in standby, which is pretty quiet. As the printer will be in a small office this is important. Is it really much quieter than the Z3100 (which has a noisy fan, even in standby)?
- Is the loss of the Gloss Enhancer a really big loss, or do the iPF6400 inks handle bronzing on gloss papers reasonably well?
The decision for me, assuming that the printers are equally good, is do I keep my really excellent Z3100 and risk not being able to get spare parts when something goes wrong? ... or do I get rid of it now and pay the $2500 or so upgrade to a new iPF6400 + set of inks?
Advice most welcome!!
Robert
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Hi,
I've an offer on my Z3100 ... so I would REALLY appreciate your advice!!
Robert
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Unfortunatelly, I had no experience with Z3100, but FWIW:
- Yes, it's true - you only have to make one linearisation on one of supported media types, and the whole rest is updated
- The spectrodensitometer gives a good calibration, you need a spectrophotometer unit to create custom calibrations for unsupported papers, but many paper manufacturers support such calibration files.
- Same here, no clogging until the terminal clog.
- Same or even better, there are also 300ml ink carts available which is more convenient than 110ml HP carts
- Roll and sheet paper load is better than in HP, drivers and print plug-in are much more convenient
- It's absolutely noiseless in standby, and very, very quiet while printing. Nonetheless, it's also much faster than HP.
- It has resin encapsulated pigment particles with splippering enhancing substance, variable pigment particle size, and it adds green colorant to black parts, so bronzing, gloss differential and scratch resistance on glossy/satin media is in the class of it's own, way better than both HP and Epson.
Here are some of my questions:
- Calibration: on the Z3100 every paper needs to be calibrated. From the reviews I've read it seems that the iPF6400 only needs to be calibrated with one paper and not for every individual paper. Is that true?
- Calibration: Does the densitometer give good calibration, or is it really necessary to have the built-in spectro?
- Head clogging: my Z3100 has shown zero problems over six years. Is the iPF6400 as good in this respect in your experience?
- Ink usage: how do the two printers compare? I've found the Z3100 to be excellent in the respect.
- Paper load: is the paper load (especially sheet paper) better than the pretty poor paper load on the Z3100?
- Printer noise: the specs show the iPF6400 at about 35dB when in standby, which is pretty quiet. As the printer will be in a small office this is important. Is it really much quieter than the Z3100 (which has a noisy fan, even in standby)?
- Is the loss of the Gloss Enhancer a really big loss, or do the iPF6400 inks handle bronzing on gloss papers reasonably well?
The decision for me, assuming that the printers are equally good, is do I keep my really excellent Z3100 and risk not being able to get spare parts when something goes wrong? ... or do I get rid of it now and pay the $2500 or so upgrade to a new iPF6400 + set of inks?
Advice most welcome!!
Robert
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Many thanks Marcin!
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Hi, I have just moved from a Z3100 to an iPF4650. Only a couple of days so far but the initial impressions are positive.
The two papers I have tried so far (Canon Satin Photo Paper & Hahnemuhle Photo Silk Baryta) have both worked well.
So far i would say the iPF4650/Hahnemuhle Photo Silk Baryta combination is even nicer than the Z3100/Ilford GFS combination that was my favorite on the HP.
I haven't noticed much of a difference in noise between the two - they both make noticeable noises at times but neither are really loud.
The 6450 goes to sleep too quickly for me and I can't find out how to change this setting.
Too early to say if it is as clog free as the Z3100 was. (belt and formatter board died on it after 8 years ! - zero clogs !)
Same goes for ink useage.
Loading roll paper is easy (I don't use sheet).
It appears that the calibration is done per paper type (in the sense that Canon are using paper type).
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Hi, I have just moved from a Z3100 to an iPF4650. Only a couple of days so far but the initial impressions are positive.
The two papers I have tried so far (Canon Satin Photo Paper & Hahnemuhle Photo Silk Baryta) have both worked well.
So far i would say the iPF4650/Hahnemuhle Photo Silk Baryta combination is even nicer than the Z3100/Ilford GFS combination that was my favorite on the HP.
I haven't noticed much of a difference in noise between the two - they both make noticeable noises at times but neither are really loud.
The 6450 goes to sleep too quickly for me and I can't find out how to change this setting.
Too early to say if it is as clog free as the Z3100 was. (belt and formatter board died on it after 8 years ! - zero clogs !)
Same goes for ink useage.
Loading roll paper is easy (I don't use sheet).
It appears that the calibration is done per paper type (in the sense that Canon are using paper type).
Thanks for the feedback!
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Unfortunatelly, I had no experience with Z3100, but FWIW:
- Yes, it's true - you only have to make one linearisation on one of supported media types, and the whole rest is updated
- The spectrodensitometer gives a good calibration, you need a spectrophotometer unit to create custom calibrations for unsupported papers, but many paper manufacturers support such calibration files.
- Same here, no clogging until the terminal clog.
- Same or even better, there are also 300ml ink carts available which is more convenient than 110ml HP carts
- Roll and sheet paper load is better than in HP, drivers and print plug-in are much more convenient
- It's absolutely noiseless in standby, and very, very quiet while printing. Nonetheless, it's also much faster than HP.
- It has resin encapsulated pigment particles with splippering enhancing substance, variable pigment particle size, and it adds green colorant to black parts, so bronzing, gloss differential and scratch resistance on glossy/satin media is in the class of it's own, way better than both HP and Epson.
Marcin said almost everything I would say, but let me add this:
I have a Z3200 and a IPF8400 working side by side, so I can make direct comparisons.
When the media configuration file is produced on a printer without the spectrophotometer such configuration file will not allow paper specific calibration, the calibration for this paper will be automatically set by the printer based on the calibration performed on the standard (canon) papers. If the media configuration file was produced on o a printer coupled with the spectrophotometer it will allow paper specific calibration (even on other printers without the spectrophotometer). The second option is better and, as Marcin said, some paper manufacturers are providing such files.
The IPF8400 is absolutely silent on standby and noisier than the Z3200 while printing due to the vacuum.
The LUCIA EX inks are excellent regarding bronzing and gloss differential when compared to other inks without the use of gloss enhancer, but it still has a lot of gloss differential. I still favor the Z3200 with the gloss enhancer to print on satin/baryta papers when the image has a lot of white "255" areas.
The black and white prints of the IPF8400 are really very good and perfectly usable, but the black and whites of the "Z3XXX" are far superior to any non dedicated black and white printer.
The canons are way faster.
The canons have slightly larger gamuts on matte papers and quite larger on glossy.
In the end I can say I am very happy with the IPF8400.
Regards.
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When the media configuration file is produced on a printer without the spectrophotometer such configuration file will not allow paper specific calibration, the calibration for this paper will be automatically set by the printer based on the calibration performed on the standard (canon) papers. If the media configuration file was produced on o a printer coupled with the spectrophotometer it will allow paper specific calibration (even on other printers without the spectrophotometer). The second option is better and, as Marcin said, some paper manufacturers are providing such files.
Thank you very much Geraldo. I'm not very clear about the calibration. If I understand you, for a new paper which does not have a media configuration file, it is necessary to produce the media configuration file on a printer that DOES have a spectrophotometer. Once there is a media configuration file, it is THEN possible to calibrate the paper roll on a printer that does NOT have a spectrophotometer. Profiling the paper can then be done using an i1Pro, for example (or use the manufacturer profile). Correct?
The iPF configuration file sounds a bit like the HP OMS configuration file, which has things like paper type, paper thickness, ink density etc. Is that so?
At any rate, if I understand you and Marcin correctly, the spectro option on the printer is only necessary if a media configuration file has not already been produced for the particular paper - either by the paper manufacturer or using an iPF with spectro. And most paper manufacturers would have configuration files for these printers.
Robert
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I'm not very clear about the calibration. If I understand you, for a new paper which does not have a media configuration file, it is necessary to produce the media configuration file on a printer that DOES have a spectrophotometer. Once there is a media configuration file, it is THEN possible to calibrate the paper roll on a printer that does NOT have a spectrophotometer.
Well, you can create media configuration files without the coupled spectrophotometer, I do it all the time, but you will not be able to perform paper-specific calibration/linearization on that paper, instead it will use the generic printer calibration that is set when you calibrate one of the canon standard papers (yes, you should have at least one roll of those canon papers around to be able to run the printer calibration). Usually the printer-level global calibration is enough, but (being a perfectionist) I very much prefer paper specific calibration when possible.
Profiling the paper can then be done using an i1Pro, for example (or use the manufacturer profile). Correct?
Yes, as usual.
The iPF configuration file sounds a bit like the HP OMS configuration file, which has things like paper type, paper thickness, ink density etc. Is that so?
Almost exactly the same, the Canon's .am1 files does not contain the ICC profile embedded as the .oms file do.
At any rate, if I understand you and Marcin correctly, the spectro option on the printer is only necessary if a media configuration file has not already been produced for the particular paper - either by the paper manufacturer or using an iPF with spectro. And most paper manufacturers would have configuration files for these printers.
That is right, except that some manufactures still provide only the ICC profile and a recommended media settings file. That way you will be able to create your own .am1 file but will not be able to perform paper specific calibrations. Canson provides media files with spectral data, Hahnemühle, on the other hand, just give you an ICC profile (and usually a bad one).
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The 6450 goes to sleep too quickly for me and I can't find out how to change this setting.
Don't know if this has been changed, but here is how to do it on older iPF generations:
http://canonipf.wikispaces.com/Sleep+Mode+Time
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Thanks :)
slightly different menu layout but sleep time is no longer set to 5 mins ;)
-Ian
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Well, you can create media configuration files without the coupled spectrophotometer, I do it all the time, but you will not be able to perform paper-specific calibration/linearization on that paper, instead it will use the generic printer calibration that is set when you calibrate one of the canon standard papers (yes, you should have at least one roll of those canon papers around to be able to run the printer calibration). Usually the printer-level global calibration is enough, but (being a perfectionist) I very much prefer paper specific calibration when possible.
Yes, as usual.
Almost exactly the same, the Canon's .am1 files does not contain the ICC profile embedded as the .oms file do.
That is right, except that some manufactures still provide only the ICC profile and a recommended media settings file. That way you will be able to create your own .am1 file but will not be able to perform paper specific calibrations. Canson provides media files with spectral data, Hahnemühle, on the other hand, just give you an ICC profile (and usually a bad one).
I'm still a bit confused ... sorry! I didn't know that spectral data was included in the .oms/.ac1 files. So I assume that with HP, when you calibrate for a paper that does not have a .oms file and you have to pick one of the standard HP papers, that the calibration process then produces the spectral data (which it can do as the printer has a spectrophotometer). So with the Canon all you can do is to do a global printer calibration based on one of the Canon papers (I guess you would need at least a gloss and a matte paper?). On the other hand, if the .ac1 file is available, then you can calibrate for this particular paper (the calibration presumably only adjusts the ink density?). If my understanding is correct (??) then I for one would not use a paper that did not have an accompanying .ac1 file (which would limit the choice of paper quite a lot!). I can also quite understand why you don't like doing this.
Is there no way of producing the spectral data for the .ac1 file using an i1Pro?
Robert
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Is there no way of producing the spectral data for the .ac1 file using an i1Pro?
Unfortunatelly no, which is a shame - spectrophotometer unit is basically an i1Pro2.
Anyway it's not really necessary, you don't really have to make individual calibration for each paper to get optimal results, the differences (if any) are negligible. Water based pigment gives consistent results on similar paper types (due to small dot gain).
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That is right, Robert.
.oms files do not need a spectral reference data as every HPZxxx has a spectrophotometer inside. As Canon IPF printers have only a densitometer (they call it multisensor/spectrodensitometer) they need the spectral data or they simply extrapolate it based on the paper type and global calibration.
Marcin is right as usual, paper specific calibration is not an absolute requirement and, to this date, I was unable to prove that it render noticeable improvements. I performed the following test:
1) Installed a Canson paper's .am1 file (with spectral data) and performed all the the usual new paper adjustments like paper advance calibration, but I did not perform the paper specific color calibration. At this point the paper is treated as a paper without the spectral data and it's calibration is extrapolated based on the global calibration.
2) I profiled the paper as I usually would and made some test prints.
3) I calibrated the paper, reprofiled after the calibration and made some new test prints.
The new profile was slightly larger but nothing really noticeable without comparing gamut volumes, the Dmax after calibration also improved by a very small margin (so small that it can be the result of read to read variations). The test prints were visually identical. That was enough to convince me that I can actually use papers without the spectral reference data. But I still prefer to have it! :D
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A great many thanks Geraldo, Marcin and everyone! - you've really clarified things for me and I'm much happier now changing to an iPF6400. I'm sure I'll miss the gloss enhancer and spectro ... but my printer is 7 years old at this stage and I'm getting pretty nervous that something will break and there will be no parts (I had to dump an Epson 4000 a few years ago because I couldn't get a new head for it ... which was a shame because apart from the famous Epson head clogs and consequent massive ink wastage it was a very good printer).
It's also a shame HP seem to have dropped this printer line because it really was a fantastic one. Looks like I'm now going to be a 100% (or nearly) Canon guy :).
Robert
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Hp hasn't dropped the Z3200 printers as far as I can see. These are the same parts as Z3100.
http://www8.hp.com/us/en/large-format-printers/designjet-printers/z3200.html
It would be nice if anyone is going to Photo Expo in Ny if they could ask the HP guys what are their plans for the future.
As long as they are still selling these printers they have to offer inks and parts for quite a number of years by law.
john
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Hp hasn't dropped the Z3200 printers as far as I can see. These are the same parts as Z3100.
http://www8.hp.com/us/en/large-format-printers/designjet-printers/z3200.html
It would be nice if anyone is going to Photo Expo in Ny if they could ask the HP guys what are their plans for the future.
As long as they are still selling these printers they have to offer inks and parts for quite a number of years by law.
john
Yes - it seems that the postscript version is still being made and sold. You can see here http://h20195.www2.hp.com/v2/GetPDF.aspx/4AA4-4150ENW.pdf that the Z3200 now comes with ps as standard.
I did a gamut comparison between the Z3200 and ipF6400 and there doesn't seem to be too much between them (Hahnemuhle profiles for Photo Glossy). The iPF has a slightly bigger gamut volume (953000 v 904000) and better greens but the Z3200 scores on the reds. The Z3200 has a better density curve and slightly better Dmax (2.32 v 2.25). But then these are Hahnemuhle profiles so they're probably not the greatest.
Interestingly, the Z3100 is much worse with a gamut volume of 716000, worse than the Z2100 at 748000. Strange when all of the inks are the same as the Z3200 except for the red.
Robert
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Hi Guys,
I've just received my new iPF6400 (first impressions: printer seems pretty nice, software good, prints good, manual horrible).
The printer comes with a few rolls of Canon Oce papers but no 'genuine' Canon papers as per the manual. I've looked for media configuration files for these papers and eventually found the support website for the papers: http://mediaguide.oce.com/Results.aspx. However, the downloadable settings are .oml files, not .am1 & .icc files.
I can't find information on how to use the .oml files to configure the printer, or whether .oml files can be used to configure the printer.
Help would be much appreciated! (BTW - I started a new topic with this question but have received no replies, so I'm hoping you are still getting notifications on this topic).
Robert
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The printer comes with a few rolls of Canon Oce papers but no 'genuine' Canon papers as per the manual. I've looked for media configuration files for these papers and eventually found the support website for the papers: http://mediaguide.oce.com/Results.aspx. However, the downloadable settings are .oml files, not .am1 & .icc files.
That is odd. The printer comes with a roll of heavyweight matt paper, your seller must have removed it and replaced with the OCE media. A 'genuine' Canon paper is actually needed for the printer to perform the basic calibration. I saw the .OML files on the link you provided, but that is new to me also. I would try to open one with the media configuration program to see if it works. You should really try to get one genuine canon paper at least.
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That is odd. The printer comes with a roll of heavyweight matt paper, your seller must have removed it and replaced with the OCE media. A 'genuine' Canon paper is actually needed for the printer to perform the basic calibration. I saw the .OML files on the link you provided, but that is new to me also. I would try to open one with the media configuration program to see if it works. You should really try to get one genuine canon paper at least.
Thanks Geraldo,
I'm going to return the papers and get some genuine Canon paper. Can you tell me what the code of the paper I should get is? I expected it would be a glossy paper but you say that it's a matt paper. It does seem that the seller kept the more expensive paper and sent me some cheaper stuff.
I've messed around with the .oml files a bit and it doesn't work with the Media Configuration tool. I saw a link for the 9xxx printers on the Oce site: they have a modified Media Configuration tool for these printers, which presumably works with their papers ... but I can't find the equivalent tool for the 6400.
Robert
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Another question, Geraldo or Marcin,
I've just done a print using a roll of Canson Platine 310gsm and I'm getting ink marks at the sides of the paper.
I have set up the paper using the Canson Platine media configuration file. Looking at the media settings it shows the correct paper, with the Standard Paper showing as Canon Photo Pro Platinum and the Head Height as Auto (Low).
It would seem that the head height is too low, which is surprising as I would have thought the .am1 file would have the correct setting. The Platine is a very thick paper - there's no info on the thickness from Canson, but I measure it at 0.55mm.
I've changed the head height to High and I'll try again, but I was wondering if this is a problem you've come across. If so, is there some way of determining what the head height should be if we know the paper thickness? The manual seems to suggest a trial-and-error approach.
Robert
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The paper that came along with mine (and with every other that I know of) is the "Canon Heavyweight Coated Paper", photo of the label below.
It is a crappy paper to be honest, but what matters is that it is one of the 'genuine' papers, papers the printer has a reference, so the printer can perform a common calibration with it and extrapolate the results to all other media. Page 833 of the manual has a list of the genuine papers that accept common calibration. Any of those paper would serve.
Here in Brazil we have a weird situation: We have Canon printers available but we do not have Canon paper on the market, so I treasure this crappy sample roll to perform the printer calibration. Sure I can import some other genuine paper when this roll ends, but it means paying an absurd price+tax.
Ink marks on the sides... you mean on the top (print side) of the paper along the edges? That can be head strikes due to paper curl. You may try to increase the vacuum strength. I never had that with Canson platine, though. Another weird thing is that the .am1 file I used has set mine with the base paper being 'Canon Premium Glossy Paper 2 280', head 'auto', vacuum 'auto'.
Maybe try downloading the media file for the 8400 as they are interchangeable.
As a side note, platine and all Canson papers have spectral data on the .am1 files, so you can perform paper specific calibration for those papers. Another reminder: Always perform paper feed adjustment when you install/add a new paper. It substantially improves the print quality.
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The paper that came along with mine (and with every other that I know of) is the "Canon Heavyweight Coated Paper", photo of the label below.
It is a crappy paper to be honest, but what matters is that it is one of the 'genuine' papers, papers the printer has a reference, so the printer can perform a common calibration with it and extrapolate the results to all other media. Page 833 of the manual has a list of the genuine papers that accept common calibration. Any of those paper would serve.
Here in Brazil we have a weird situation: We have Canon printers available but we do not have Canon paper on the market, so I treasure this crappy sample roll to perform the printer calibration. Sure I can import some other genuine paper when this roll ends, but it means paying an absurd price+tax.
Ink marks on the sides... you mean on the top (print side) of the paper along the edges? That can be head strikes due to paper curl. You may try to increase the vacuum strength. I never had that with Canson platine, though. Another weird thing is that the .am1 file I used has set mine with the base paper being 'Canon Premium Glossy Paper 2 280', head 'auto', vacuum 'auto'.
Maybe try downloading the media file for the 8400 as they are interchangeable.
As a side note, platine and all Canson papers have spectral data on the .am1 files, so you can perform paper specific calibration for those papers. Another reminder: Always perform paper feed adjustment when you install/add a new paper. It substantially improves the print quality.
Many thanks Geraldo.
I've updated all the software to the latest versions. I've also checked both the Platine configurations for the 6400 and the 8400 and they both use the Canon Photo Paper Pro Platinum (so I guess they must have updated the files since you downloaded them).
The settings are
Head Height: Auto(lowest);
Vacuum Auto (weak)
I did a paper feed adjustment as you suggested (after changing the Vacuum to Strong). After the adjustment the vacuum was set back to weak, so in the following steps in the Media Configuration I changed it back to Strong. It seems strange that the vacuum setting comes after the paper feed adjustment.
I then did a calibration on the Platine. Everything now seems to be fine with no more marks on the edges of the paper, so it seems the vacuum change has done the job.
I'm still a little confused about the need for a Genuine Canon paper for calibration. I take it that you need this to calibrate a paper that doesn't come with an .am1 file (so you don't have the spectral data for it)?
So I assume you set up the paper media settings for this custom paper based on an existing paper type (like the Canon Photo Paper Pro Platinum, say) and then use the calibration from the Genuine Paper (say HW Coated) for this paper ... is that correct?
If that's the case, could you not use, for example, the calibration on the Platine just as well as the calibration from one of the Genuine Canon papers?
I take it I'm missing a vital link in the process!
Robert
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I'm still a little confused about the need for a Genuine Canon paper for calibration. I take it that you need this to calibrate a paper that doesn't come with an .am1 file (so you don't have the spectral data for it)?
That is right. Actually anyone can make a .am1 file, but only the .am1 files made on the IPF6450 with the coupled spectro will have spectral reference data allowing paper specific calibration.
So I assume you set up the paper media settings for this custom paper based on an existing paper type (like the Canon Photo Paper Pro Platinum, say) and then use the calibration from the Genuine Paper (say HW Coated) for this paper ... is that correct?
You do not need to select manually the genuine paper used for calibration. Every time you calibrate a genuine paper (any) the printer will use that info to update it's internal calibration and it will be applied to all paper that is not using paper specific/unique calibration.
If that's the case, could you not use, for example, the calibration on the Platine just as well as the calibration from one of the Genuine Canon papers?
No, as it is not a genuine canon paper the printer will not use it this way, even when you have the spectral data. Probably a way to push the sales of Canon papers.
Tomorrow, when I get back to the studio, I will download again the settings and compare.
Well, at least you got rid of the marks on the edge.
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It seems strange that the vacuum setting comes after the paper feed adjustment.
Hi Robert, that is a very good question. I thought about it myself too until I worked with the SU-21 spectro on a iPF6460. I noticed that when creating unique calibration data for new media, it runs the paper feed adjustment again. So I figured, one should skip this step during the new media build. The MCT will warn you of problems but just skip it first, determine your vacuum strength and head height and create the .am1 file. After it is created, then click on edit, and run the paper feed adjustment. That is the way it should be done. or else the adjustment may be wildly inaccurate, because the MCT may pick different head height and vacuum strength settings. It is easy to check if you have a pocket microscope. Not many know about doing it this way!
Don't forget to export your .am1 files when you are done creating the new adjustment data, and back them up.
I've just done a print using a roll of Canson Platine 310gsm and I'm getting ink marks at the sides of the paper.
The paper path of the iPF64XX may be to blame. Testing extensively with my dealer's demo printer, I always get head strikes at the beginning of the roll, because the natural curl of the paper raises the front end just slightly too high as it passes over the platen. After the first bit of the roll has gone through, it prints just fine. Sometimes the lowest head height is ok, but I find it safer to keep it at 'low'. I still had head strikes, again only for the intial three inches or so, after which it was fine. Vacuum strength should be strong or strongest (I prefer the latter). The vacuum is able to hold down the paper more in the center so that's why the marks are only on the sides.
A simplified drawing:
(https://dl.dropboxusercontent.com/u/15547362/ipf64XX-paper-path.png)
Do beware the pizza wheels at the ejection point of the paper path. If the paper is too curly, it will impact the pizza wheels. While they are there to guide the paper, it marks glossy media like Patine with tiny perforated markings. Watch out for that. Again it only happens for the initial portion of paper. Guiding it with your fingers as it passes out is how I worked around the problem.
If that's the case, could you not use, for example, the calibration on the Platine just as well as the calibration from one of the Genuine Canon papers?
No, as it is not a genuine canon paper the printer will not use it this way, even when you have the spectral data. Probably a way to push the sales of Canon papers.
Tomorrow, when I get back to the studio, I will download again the settings and compare.
Well, at least you got rid of the marks on the edge.
Scott Martin has advocated calibrating on your favorite (high quality) paper that you always have lying around, not genuine Canon media, especially if that is hard to get where you are. (Same problem here in Singapore Geraldo!) The point is that when you next need to recalibrate, you will have that paper in stock and you don't have to re-do all your profiles, which you will need if you calibrated to a different paper. He explained to me that the calibration process is in fact a simple linearizing function, no matching to any reference data. The printer measures paper white and dmax, and adjusts all the patches in between to fall in regular steps. He claimed to have spoken with Canon engineers who first explained it to him said it is ok to use third party high quality papers for calibration.
As Geraldo pointed out, these new iPFX4XX have media files associated with "common calibration" or "unique calibration" properties. Common calibration applies calibration information across all media types after calibration is performed once. It is highly recommended that you do this - no in fact it must be the first thing you do when setting up the printer. I'm less sure if unique calibration is useful. Imagine a print head swap down the road - instead of performing one common calibration and be done, you will have that to do that plus all your third party papers unique calibrations. A lot of additional paper and some ink to be wasted.
I have performed common calibration on third party papers with no problems. It is best to use very high quality media, and keep the same roll around for re-calibrations in the future, in case the paper formula is changed down the road and a new roll invalidates all your profiles.
My own experiments also indicate that common calibration on glossy media yields better gamut performance than matte media. Profiles for matte media are about 4 - 6% larger, comparing to calibration made on matte paper. The improvement on glossy is only 1-2% larger, within ColorThink Pro's margin of error in gamut calculations so no conclusions there.
Coming back to if calibrations should be done on genuine paper - I'm not 100% sure if it will be better or you will see no difference, or perhaps it might be worse. Worse perhaps because calibrating to your favorite glossy paper might set up the printer more optimally (my guess is that's most likely the case). But perhaps looking at the way the unique calibration spectral data is built using the SU-21 spectro and the iPF64XX printer might reveal something - the MCT advises to perform common calibration on genuine paper before printing out the color target - implying that the printout of the color target is affected by the calibration - hmmm.
Geraldo, my own tests on unique calibration vs common calibration shows minimal differences just as you reported in a different thread. Again matte media shows more significant differences than glossy media, though only slightly. Certain ranges of color are affected more than others, but there is also a tiny improvement in deepest black separation, which is always nice. On glossy it almost seems not worth the effort, but I do it anyway. Now that I have an iSis, it is much easier to re-profile whenever I need to. Plus I have also noticed that sometimes re-calibrations shift the printer behavior enough to warrant re-profiling. Still, perhaps it is always better to have unique calibration for the paper you are using, to account for any special (subtle) differences.
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Hi Samuel,
Scott Martin has advocated calibrating on your favorite (high quality) paper that you always have lying around, not genuine Canon media, especially if that is hard to get where you are.
And how you do that? According to the manual and as far as I managed to test, the printer does not accept a common calibration on any other paper than genuine canon paper. Do you simply fool the printer, loading your favorite paper as if it was a genuine?
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Hi Samuel,
And how you do that? According to the manual and as far as I managed to test, the printer does not accept a common calibration on any other paper than genuine canon paper. Do you simply fool the printer, loading your favorite paper as if it was a genuine?
Yes, Geraldo, you simply feed your favourite paper in and select a media setting suitable for that paper, then hit auto calibration.
I don't see why genuine paper must be used since many media settings are actually the same, just different names, plus some Canon paper is just rebranded, like Museum Etching. My feeling is that it is just simple linearizing going on.
Also interesting to note is that the printer prints both matte and glossy black when calibrating, which led me to raise the question - is calibrating on matte or glossy better? The behavior of matte black on glossy paper and glossy black on matte paper is somewhat unpredictable, and does seem to affect calibration.
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I don't see why genuine paper must be used since many media settings are actually the same, just different names, plus some Canon paper is just rebranded, like Museum Etching. My feeling is that it is just simple linearizing going on.
Hummm... I have to test that. At first I thought It would not be a good idea as different papers, although similar, may have slightly different white points and tint and that different reading could mess the common calibration. But it may not be the case. I will give it a try on the next calibration.
Curiously, the IPF8400 manual advises using glossy papers for the common calibration preferably, but they ship the printer with a matte roll.
The HPZ3200 printers actually print with both blacks (matte and glossy) on matte papers, but only with the glossy black on glossy papers. The glossy black remains matte on matte papers and with a slightly better DMax, so the Z3200 has actually four blacks/grays when working with matte paper. I don't think Canon uses this trick.
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Geraldo,
The Z3100/Z3200 have some matte media presets that use the quad inkset but not all matte media presets have all 4 inks in use, usually the PK is taken out then. There is a document describing the variety of inks used per media preset + the ink limit figure. On thinner ordinary matte papers for example one of the grey inks may not be used either to reduce the inkload.
There are several 230 gsm papers around that have a spectral plot similar to the Canon Heavyweight Matte Coated. Rebrands of the original made by Felix Schoeller. Their spectral plots indicate a slightly higher OBA content. Could as well be caused by fresher samples with less OBA deterioration.
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Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
September 2014, 650+ inkjet media white spectral plots.
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Another question, Geraldo or Marcin,
I've just done a print using a roll of Canson Platine 310gsm and I'm getting ink marks at the sides of the paper.
I have set up the paper using the Canson Platine media configuration file. Looking at the media settings it shows the correct paper, with the Standard Paper showing as Canon Photo Pro Platinum and the Head Height as Auto (Low).
It would seem that the head height is too low, which is surprising as I would have thought the .am1 file would have the correct setting. The Platine is a very thick paper - there's no info on the thickness from Canson, but I measure it at 0.55mm.
I've changed the head height to High and I'll try again, but I was wondering if this is a problem you've come across. If so, is there some way of determining what the head height should be if we know the paper thickness? The manual seems to suggest a trial-and-error approach.
Robert
Robert, i recently had a job where i used the 6450. Had similar headstrikes, turned out the paper thickness was not set properly. In my case is should have been 0.6mm, but the canon setting was 0.1mm. After adjusting things went fine.
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Robert, i recently had a job where i used the 6450. Had similar headstrikes, turned out the paper thickness was not set properly. In my case is should have been 0.6mm, but the canon setting was 0.1mm. After adjusting things went fine.
How do you see the head height in mm? I only see Super Low, Lowest, Low, Standard, High and Highest.
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The HPZ3200 printers actually print with both blacks (matte and glossy) on matte papers, but only with the glossy black on glossy papers. The glossy black remains matte on matte papers and with a slightly better DMax, so the Z3200 has actually four blacks/grays when working with matte paper. I don't think Canon uses this trick.
Canon glossy black ink prints with lower dmax on matte papers than their own matte black, the opposite of the HP. I don't think it uses any glossy black when printing on matte papers.
Curiously, the IPF8400 manual advises using glossy papers for the common calibration preferably, but they ship the printer with a matte roll.
Interesting point. Probably partly because highly textured matte papers mess up the measurement step.
The standard calibration patches are also super tiny. And printed with the print mode set to Highest, bidirectional. Very coarse output, not high quality at all. The patches for what Canon calls "high quality calibration" on printers with the SU-21 prints far larger patches, but still not using the highest quality print mode.
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There are several 230 gsm papers around that have a spectral plot similar to the Canon Heavyweight Matte Coated. Rebrands of the original made by Felix Schoeller. Their spectral plots indicate a slightly higher OBA content. Could as well be caused by fresher samples with less OBA deterioration.
Thank you Ernst, that is valuable information. Another reason the Canon calibration cannot be too reliant on reference data, if it is at all. White points will always shift from batch to batch and there is OBA burnout to consider.
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How do you see the head height in mm? I only see Super Low, Lowest, Low, Standard, High and Highest.
Was digging around a bit and I see such an option in the canon calibration link software package manual.
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Thanks all!
Regarding common calibration with a non-genuine paper, I did this (by mistake) when I first calibrated the printer, because the roll shipped with the printer was an Oce 190gsm glossy paper and I didn't have any genuine Canon paper. So I picked the Canon 170gsm glossy paper and sure enough, all of the paper calibrations were then set to the Canon 170gsm (obviously the printer isn't smart enough to know that you've fooled it :)).
Still ... I don't like doing this because the Oce paper is certainly going to be different to the Canon 170gsm genuine paper: different white, different amount of optical brighteners etc., so unless the calibration is super-dumb (in which case why bother printing different color patches?) and doesn't reference the spectral data, the calibration is going to be wrong. If we profile the paper after the 'cheat' calibration, then the profile will correct for the wrong calibration, so we'll be OK, but if we use the manufacturer profile then we might have problems.
Which brings me onto the subject of optical brighteners. It would seem to me that calibrating a paper with a lot of OBA and then using this calibration on a paper that has none, is most likely not a very good idea. So I wonder if a solution would be:
- 1. For common calibrations use a paper that has a low amount of OBA so it will be somewhere in between the two extremes
- 2. Use unique calibrations for papers for which we have the media configuration files (with spectral data)
- 3. For papers for which we do not have the spectral data, do a cheat unique calibration using a paper close to the target paper (so, for example, use a matte genuine paper with no OBA if the target paper is a matte paper with no OBA)
- 4. Profile the papers in all cases and do not use the supplier icc file except for 2. (but even then, better to produce a custom profile).
I would think that it would be OK to recalibrate on new rolls without having to reprofile (even for common calibrations), providing the papers are high quality papers.
What do you think?
Robert
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Was digging around a bit and I see such an option in the canon calibration link software package manual.
Could you tell me how to set the paper thickness in mm? I can't find this.
Robert
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Was digging around a bit and I see such an option in the canon calibration link software package manual.
(https://dl.dropboxusercontent.com/u/15547362/Untitled.png)
This is all I could find.
Could you tell me how to set the paper thickness in mm? I can't find this.
Neither can I. I have some evidence of what the low, standard, high etc head settings correspond to in mm, but it is not clear. For Super low the head is already over 1mm above the platen.
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Hi Robert,
Have you looked carefully at the LEDs used during measurement when performing calibration? Green is used to measure paper white, and the blue LED is used for the first set of patches, and then red for the second set of patches - I may have gotten that mixed up slightly.
The printer is not able to measure anything other than density unless you have the SU-21 spectro unit. I believe Scott Martin is right in saying it is just a straightforward linearizing step, nothing else. No reference data would be needed if the printer indeed performs that way.
We don't know the SPD of the LEDs and exactly how the calibration is performed so it is difficult to say how OBAs will affect the measurements. Test and let us know?
I would think that it would be OK to recalibrate on new rolls without having to reprofile (even for common calibrations), providing the papers are high quality papers.
What do you think?
I don't think so. Hahnemuhle Photo Rag 308 has been reformulated, as an example.
Calibrate once, print out a profiling target, calibrate again, print out a profiling target and compare measurements. You will see that it varies enough. Usually if the printer warrants a re-calibration, it should be re-profiled. The re-calibration is heaven sent for less fussy uses, or uses who have profiles made by others for them.
- 2. Use unique calibrations for papers for which we have the media configuration files (with spectral data)
- 3. For papers for which we do not have the spectral data, do a cheat unique calibration using a paper close to the target paper (so, for example, use a matte genuine paper with no OBA if the target paper is a matte paper with no OBA)
- 4. Profile the papers in all cases and do not use the supplier icc file except for 2. (but even then, better to produce a custom profile).
2. My question here is if the spectral data was produced with the printer properly calibrated before the target was printed. I'm not sure if the manufacturer's .am1 files were all optimally produced that way. In addition, they usually have chosen suboptimal settings for their papers.
3. That is definitely not a good idea at all. You are much better of using the common calibration here and just re-profiling. And if you really want to do this, create another version of this media type or else when you want to use the paper it was originally created for, the calibration data is wrong.
4. The supplier profiles are really not good at all. I see all sorts of problems. Even the best of them do not render the skin tones properly. These printers still don't print as close as you would think.
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Hi Robert, that is a very good question. I thought about it myself too until I worked with the SU-21 spectro on a iPF6460. I noticed that when creating unique calibration data for new media, it runs the paper feed adjustment again. So I figured, one should skip this step during the new media build. The MCT will warn you of problems but just skip it first, determine your vacuum strength and head height and create the .am1 file. After it is created, then click on edit, and run the paper feed adjustment. That is the way it should be done. or else the adjustment may be wildly inaccurate, because the MCT may pick different head height and vacuum strength settings. It is easy to check if you have a pocket microscope. Not many know about doing it this way!
I used an .am1 file from Canson, which seemed to have wrong head height/vacuum settings (but it could be the paper path/start of roll problem you mention). I changed the vacuum, then did a paper feed adjustment by going through the edit and this seemed to reset the vacuum to auto ... so I reset it back to Strong before doing a calibration. But it's possible I made a mistake somewhere, so I'll try again.
So it would seem that with existing .am1 files, we should do an edit, skip the paper feed and set the other parameters like head height and vacuum, then go back and to the paper feed adjustment before doing a calibration, profiling. Is that correct?
If we don't have an .am1 file, then create one and go through the same procedure as above.
The paper path of the iPF64XX may be to blame. Testing extensively with my dealer's demo printer, I always get head strikes at the beginning of the roll, because the natural curl of the paper raises the front end just slightly too high as it passes over the platen. After the first bit of the roll has gone through, it prints just fine. Sometimes the lowest head height is ok, but I find it safer to keep it at 'low'. I still had head strikes, again only for the initial three inches or so, after which it was fine. Vacuum strength should be strong or strongest (I prefer the latter). The vacuum is able to hold down the paper more in the center so that's why the marks are only on the sides.
Yes, it seems that the head strikes were only after the initial paper load. But this was not a new roll, actually it was near the end of the roll (where there's going to be even more curling). Also I hadn't tied down the paper (but did have in in plastic), so the leading half meter might have been even more curled than it would normally be. That's a problem with rolls of these heavy papers!
I take it the .am1 should have things like head height and vacuum settings? Seems strange then that Canson would have the settings at Auto(lowest) and Auto(weak) for a thick curly paper like the Platine (must try the Baryta and see what the settings are for that).
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Do beware the pizza wheels at the ejection point of the paper path. If the paper is too curly, it will impact the pizza wheels. While they are there to guide the paper, it marks glossy media like Patine with tiny perforated markings. Watch out for that. Again it only happens for the initial portion of paper. Guiding it with your fingers as it passes out is how I worked around the problem.
I haven't seen this problem, but I would be interested in how you guide the paper with your fingers. I don't suppose there's any risk of getting the fingers cut off is there? :)
I'm less sure if unique calibration is useful. Imagine a print head swap down the road - instead of performing one common calibration and be done, you will have that to do that plus all your third party papers unique calibrations. A lot of additional paper and some ink to be wasted.
Yes, that's certainly a good point, especially if one uses many different papers (or 15m rolls of expensive papers like the Canson Platine/Baryta/Photo HiGloss papers ... by the time you've done a paper feed adjustment and a calibration you would need to put in a new roll!).
Plus I have also noticed that sometimes re-calibrations shift the printer behavior enough to warrant re-profiling.
That's worrying and would indicate that the calibration process is not accurate.
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Hi Robert,
Have you looked carefully at the LEDs used during measurement when performing calibration? Green is used to measure paper white, and the blue LED is used for the first set of patches, and then red for the second set of patches - I may have gotten that mixed up slightly.
The printer is not able to measure anything other than density unless you have the SU-21 spectro unit. I believe Scott Martin is right in saying it is just a straightforward linearizing step, nothing else. No reference data would be needed if the printer indeed performs that way.
We don't know the SPD of the LEDs and exactly how the calibration is performed so it is difficult to say how OBAs will affect the measurements. Test and let us know?
I don't think so. Hahnemuhle Photo Rag 308 has been reformulated, as an example.
Calibrate once, print out a profiling target, calibrate again, print out a profiling target and compare measurements. You will see that it varies enough. Usually if the printer warrants a re-calibration, it should be re-profiled. The re-calibration is heaven sent for less fussy uses, or uses who have profiles made by others for them.
2. My question here is if the spectral data was produced with the printer properly calibrated before the target was printed. I'm not sure if the manufacturer's .am1 files were all optimally produced that way. In addition, they usually have chosen suboptimal settings for their papers.
3. That is definitely not a good idea at all. You are much better of using the common calibration here and just re-profiling. And if you really want to do this, create another version of this media type or else when you want to use the paper it was originally created for, the calibration data is wrong.
4. The supplier profiles are really not good at all. I see all sorts of problems. Even the best of them do not render the skin tones properly. These printers still don't print as close as you would think.
So then really, from what you say, the best solution is to do a common calibration (for all papers) using a good quality paper (preferably a Canon paper, but this isn't essential) and then profile all the papers after the initial common calibration (so that the profile will correct for the slightly dodgy calibration) and never use manufacturer profiles.
The calibration is putting the printer into a reasonable good known state, and providing we use the same roll to recalibrate, the calibration will keep the printer in this reasonable good known state (so that we don't keep having to reprofile the papers).
If we add a new paper then we should run the common calibration again before profiling the new paper.
I would be interested to know if the calibration/profiling using a 6450 is as good as doing it this way? The reason I ask is that with the Z3100 the profiling target uses very few patches, so it would be very unlikely to do as good a job as an i1Pro/2 with a good-sized target. I assume the calibration of the 6450 would be better (than the 6400/8400), but that the profiling might be worse (but I've no idea how many patches the 6450 uses for profiling).
Robert
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Hi Robert,
Have you looked carefully at the LEDs used during measurement when performing calibration? Green is used to measure paper white, and the blue LED is used for the first set of patches, and then red for the second set of patches - I may have gotten that mixed up slightly.
I'm still a bit concerned about the OBA side of things. I would have thought that unless the LEDs have no UV or that the densitometer has a UV filter, that the OBAs will affect the calibration: for example, the white will be bluer and brighter than it would be without UV. Perhaps that doesn't matter if we are profiling the papers, but it could make quite a difference if we use manufacturer-supplied profiles with common calibration (if we use manufacturer supplied profiles I would think that we should do a unique calibration on the paper).
I'm thinking that this whole thing is potentially quite messy, and the best thing is to use a common calibration using a paper that has minimal or no OBAs and always profile the papers.
Robert
Robert
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I used an .am1 file from Canson, which seemed to have wrong head height/vacuum settings (but it could be the paper path/start of roll problem you mention)...
I take it the .am1 should have things like head height and vacuum settings? Seems strange then that Canson would have the settings at Auto(lowest) and Auto(weak) for a thick curly paper like the Platine (must try the Baryta and see what the settings are for that)
Canson uses the "Auto" setting for head height and vacuum setting, which is possibly just a safe bet on their side. They certainly don't want to invite complaints that a head strike destroyed a user's print head because of their settings. Leaving it to auto allows the blame to fall to Canon. Unfortunately our dumb machines still cannot figure this out on their own so the settings that were determined are suboptimal.
The .am1 files will contain the head height and vacuum settings. If you import the .am1 file made using the MCT of another iPFX4XX printer, all settings return to their default values, except for the base media setting and inking setting. I learned that the hard way after I imported .am1 files I created with the iPF6460 and SU-21 for my iPF8410.
So it would seem that with existing .am1 files, we should do an edit, skip the paper feed and set the other parameters like head height and vacuum, then go back and to the paper feed adjustment before doing a calibration, profiling. Is that correct?
Yes, whatever you do, determine the head height and vacuum settings first, then do the paper feed adjustment last.
That's a problem with rolls of these heavy papers!
Canson's papers are actually quite well behaved in that respect. Platine comes off the roll almost flat - very nice. It has got to do with the paper path design of the iPFX6XX printers, which bend the paper counter to the direction of the paper curl. (http://www.luminous-landscape.com/forum/index.php?topic=73005.msg579728#msg579728) My iPF8410 printer has a curved paper path, curved in the same way as the paper is. It's is a fantastic design, better than Epson's in my opinion, unless one is needing to print on metal or stiff card that requires a straight paper path.
I would be interested in how you guide the paper with your fingers. I don't suppose there's any risk of getting the fingers cut off is there? Smiley
Nope, not if you are quick and know what you are doing. 8) Don't do a Mr Bean! The exit path of the paper is large enough. Look for the silver pizza wheels on the top side. Before the paper reaches that point, just guide it with your fingers by holding it down a little. After enough of the paper has been fed through, it will bend downwards naturally and you can let go.
Yes, that's certainly a good point, especially if one uses many different papers (or 15m rolls of expensive papers like the Canson Platine/Baryta/Photo HiGloss papers ... by the time you've done a paper feed adjustment and a calibration you would need to put in a new roll!).
Yup, it uses an insane amount of paper for the adjustments. Notice how much paper gets used for a simple calibration print out? Crazy. Not to mention all the wasted time too.
That's worrying and would indicate that the calibration process is not accurate.
Depends on your definition of accurate. I should mention I am unbelievably fussy about this, so perhaps re-calibration is good enough for you. I suggest to test it for yourself. Calibrate once, make a print, then calibrate again, make a print. Can you see a difference? Or can you measure a difference? How big (or small) is it?
So then really, from what you say, the best solution is to do a common calibration (for all papers)
Yes, I think this is the best for the majority of users. It's the least painful method.
If we add a new paper then we should run the common calibration again before profiling the new paper.
No!! The common calibration only needs to be performed once. It is applied to all other media .am1 files and any new .am1 files that you install even after calibration. You only run common calibration again if your printer drifts, or you swap a print head.
If you run common calibration on every new paper you try all your previous profiles will be invalidated.
I assume the calibration of the 6450 would be better (than the 6400/8400)
I don't understand what you mean. The on-board densitometers of all these printers are the same and give equal calibration quality.
I think you refer to the SU-21 unit, which can be placed on both the 6400 and 6450 and their S cousins. The 6450 cannot make profiles on its own.
I'm still a bit concerned about the OBA side of things.
Anyone interested in print permanence needs to be anyway. Why would you select a paper loaded with OBAs, say like Epson Exhibition Fiber? If you print on high quality papers like the Canson Platine you use, I don't see any reason to worry about this. Besides, it works great all the same. I have calibrated on papers with moderate amounts of OBAs in the paper core (not ink layer) with excellent results.
Indeed profiling does help equalize things a lot. Calibration helps more to prevent things likeblocking up in the shadows, which a profile cannot help in. And of course a sort of standard to return to on a regular basis, or after print head change.
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Nope, not if you are quick and know what you are doing. 8) Don't do a Mr Bean! The exit path of the paper is large enough. Look for the silver pizza wheels on the top side. Before the paper reaches that point, just guide it with your fingers by holding it down a little. After enough of the paper has been fed through, it will bend downwards naturally and you can let go.
I take it you need to have the top cover open to do that (or else have very long, thin, bendy fingers ;)).
Yup, it uses an insane amount of paper for the adjustments. Notice how much paper gets used for a simple calibration print out? Crazy. Not to mention all the wasted time too.
It's something that has always annoyed me with HP also: instead of going across the paper it goes along it, wasting masses amount needlessly. One thing I found with the Z3100 is that you can feed A4 sheets into it for calibrations, which saves a whole lot of paper ... maybe the same with the Canon? I'll give it a try.
Depends on your definition of accurate. I should mention I am unbelievably fussy about this, so perhaps re-calibration is good enough for you. I suggest to test it for yourself. Calibrate once, make a print, then calibrate again, make a print. Can you see a difference? Or can you measure a difference? How big (or small) is it?
Oh, I'm an obsessive-compulsive perfectionist! If it's not perfect it goes in the bin. If recalibration requires re-profiling then that's what I'll have to do. I'll do some checks and see what sort of dE differences there are between calibrations.
No!! The common calibration only needs to be performed once. It is applied to all other media .am1 files and any new .am1 files that you install even after calibration. You only run common calibration again if your printer drifts, or you swap a print head.
If you run common calibration on every new paper you try all your previous profiles will be invalidated.
Well, they will be invalidated to the extent that the calibrations are inconsistent. If the calibration was accurate and you always used the same media for your common calibration then it shouldn't matter how often you recalibrate.
How do you know when your printer has drifted? Do you print a test target every now and then and do a check? Or do you rely on the printer to tell you when it's time?
I don't understand what you mean. The on-board densitometers of all these printers are the same and give equal calibration quality.
I think you refer to the SU-21 unit, which can be placed on both the 6400 and 6450 and their S cousins. The 6450 cannot make profiles on its own.
Yes ... I meant the printer with the spectro (the 6460, I guess).
Anyone interested in print permanence needs to be anyway. Why would you select a paper loaded with OBAs, say like Epson Exhibition Fiber? If you print on high quality papers like the Canson Platine you use, I don't see any reason to worry about this. Besides, it works great all the same. I have calibrated on papers with moderate amounts of OBAs in the paper core (not ink layer) with excellent results.
Indeed profiling does help equalize things a lot. Calibration helps more to prevent things like blocking up in the shadows, which a profile cannot help in. And of course a sort of standard to return to on a regular basis, or after print head change.
The reason I'm concerned about OBAs is because I also use the Canson Photo HiGloss 315gsm (for prints that are mounted behind acrylic, because I need a thick paper with a very smooth surface, so that the paper sticks to the acrylic perfectly). This is the only paper I use that has OBAs. So do I common calibrate with a paper that has OBAs, or one that does not, seeing as how I'm using papers that have OBAs and papers that do not?
I suppose the profile would correct for any differences, so I'm probably being a bit neurotic :). So I'm thinking now of using a roll of Canon Photo Glossy 170gsm for the common profiling. Any advice to use a different paper?
Robert
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I have one or two (or maybe three) more questions ... I hope I'm not pushing my luck!
- Is 16-bit printing on Windows only possible using the Canon Print Plug-in? I don't see any settings in the driver that would allow 16-bit printing (whereas there seems to be on the Mac).
- For profiling papers, do you have a recommended number of patches? I have an i1Pro2 and I've used both ArgyllCMS, and also i1Profiler. They both seem to give pretty good results ... I usually use 2584 patches, which just fits onto 4 A4 sheets (or 1 A2 sheet). I haven't done any comparisons with less/more patches so I'm just flying blind.
- When you're checking your print quality (for example after a recalibration), do you use the Data Analysis workflow in i1Profiler? I haven't used it but I guess it would make sense to print an A4 target, recalibrate, print the target again, scan both and compare them using the Data Analysis. This would be OK to check color drift, but I don't see a way with i1Profiler to validate the target print against the chart Lab values. Any suggestions? Maybe ArgyllCMS would be an option if it can't be done with i1Profiler.
Robert
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I take it you need to have the top cover open to do that (or else have very long, thin, bendy fingers
Absolutely not. I wrote "exit path". You reach in from the front, and only a little ways in. Find the pizza wheels first! That's your marker. I don't have long thin bendy fingers. I'm not about to go back to my dealer's at this point and make a video of all this, and you don't seem to have any trouble with the pizza wheels. This was one of the more annoying issues I had with the smaller format Canons, coming from an iPF5000 more than 8 years ago. The paper path design is not the best.
instead of going across the paper it goes along it, wasting masses amount needlessly.
If you purchase the SU-21 for your printer, it distributes the patches across the width of a 17 inch roll to minimize paper wastage. But I don't think the unit is worth the price.
Oh, I'm an obsessive-compulsive perfectionist! If it's not perfect it goes in the bin.
Haha I understand that feeling. Would it irk you to know that your i1 Pro 2 is not as consistent as we would like it to be? I tore my hair out for years over this.
If the calibration was accurate and you always used the same media for your common calibration then it shouldn't matter how often you recalibrate.
I dug up my notes of one of the tests I did on recalibration at the start of this year, and I noted a max 1dE2k difference, but I was measuring with an i1 Pro 2 then. Same roll of paper. I'm not sure how much of that error is user error. Then I just did a recalibration on Epson Hot Press Natural, two different rolls, different lot numbers. I measured with my iSis for this one. Max 1.2 dE2k. So I should say it can be reasonably consistent, but bordering on the need for re-profiling for me. It would be good to know what kind of numbers you are seeing too.
How do you know when your printer has drifted? Do you print a test target every now and then and do a check? Or do you rely on the printer to tell you when it's time?
Scott Martin recommends every 6 months for low volume users, and every 3 months for high volume users. Yes, I actually print out my profiling target to do a check, since I am going to measure it anyway, it might as well serve two purposes. If it is different, the profile would still be useful for the next print job, being able to correct for most of the drift. I have not known about the usefulness of calibration long enough and used different machines in different atmospheric environments to provide useful numbers besides this. The Canon Color Calibration Management Console also has a status timer which tells you when to recalibrate. I'm not sure how long the countdown is and I don't use that.
Yes ... I meant the printer with the spectro (the 6460, I guess).
The 6460 is the Southeast Asian name of the 6450. Canon adds 10 to all the X4XX printer names. I believe they modify the ink cartridge keyed slots for these printers so folks in Europe and USA don't buy our inks, which are somewhat cheaper.
The spectro might offer slightly more accurate calibrations, but that kind of differences are worked out with excellent profiles. After profiling, I considered it to make no difference at all to the final output quality, after testing carefully. The consistency of the calibration is much more important. I am about to run more tests on this now that I have my iSis and write up an extensive article on what we have discussed so far. I also rate the printer's performance as far more important. I have uncovered multiple issues leading to less than optimal quality for these newer Canon printers. When all the stars align, the dot pattern is ridiculously fine, better in some color regions than Epson OEM driver, and more consistent across the color range.
So do I common calibrate with a paper that has OBAs, or one that does not, seeing as how I'm using papers that have OBAs and papers that do not?
Does not matter at all to me. It is about consistency - pick one and stick with it. Especially if you choose media with OBAs, keep the same roll around for future recalibrations.
So I'm thinking now of using a roll of Canon Photo Glossy 170gsm for the common profiling. Any advice to use a different paper?
That paper is very thin and translucent and the black plastic of the platen would affect calibration to some extent, although in a consistent fashion. I'm not sure how it would affect calibration as I don't have any around to test against - I saw it only twice when Canon engineers brought it down for my printer repair. Actually, it would be great if you could test it against your Canson Photo Higloss paper and see what kind of differences you can measure.
My preference is to calibrate on a glossy paper that can take the highest ink loads for the greatest dmax. Hahnemuhle Photo Rag Bartya, Harman by Hahnemuhle Gloss Baryta are two I have used successfully before. I noted a gamut increase of just over 4% for matte media when calibrating to a high quality glossy paper, instead of matte paper. I used the same matte paper for the profiling gamut test - instead of favoring calibration on the same paper, it was actually better when I calibrated to glossy.
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I have one or two (or maybe three) more questions ... I hope I'm not pushing my luck!
- Is 16-bit printing on Windows only possible using the Canon Print Plug-in? I don't see any settings in the driver that would allow 16-bit printing (whereas there seems to be on the Mac).
- For profiling papers, do you have a recommended number of patches? I have an i1Pro2 and I've used both ArgyllCMS, and also i1Profiler. They both seem to give pretty good results ... I usually use 2584 patches, which just fits onto 4 A4 sheets (or 1 A2 sheet). I haven't done any comparisons with less/more patches so I'm just flying blind.
- When you're checking your print quality (for example after a recalibration), do you use the Data Analysis workflow in i1Profiler? I haven't used it but I guess it would make sense to print an A4 target, recalibrate, print the target again, scan both and compare them using the Data Analysis. This would be OK to check color drift, but I don't see a way with i1Profiler to validate the target print against the chart Lab values. Any suggestions? Maybe ArgyllCMS would be an option if it can't be done with i1Profiler.
Robert
No problem Robert. I am happy to share what I know. It would be fantastic if you could run some of the tests yourself and report your findings. They might be different from my observations and I think we would both want to know why - and understand these printers better.
1. The plug-in supports 16 bits, but the on-board hardware may or may not quantize the bits to 12. Scott Martin said they did on the X1XX printers. (http://canonipf.wikispaces.com/Plugin+Bit+Depth) I don't know about the X4XX printers.
2. We could talk about this for weeks, it is such an interesting topic. Generally speaking, 2000+ patches (well distributed or well chosen sampling) is at the point of diminishing returns. You are safe here. With active calibration, the X4XX printers are very linear and actually need less patches to profile well. Like you, my preference is also to fill my chosen paper size with patches to reduce paper wastage.
3. I used ColorThink Pro for comparing my data. I just did a quick look at i1Profiler's Data Analysis function. It performs just as well. Being able to parse its own mxf measurement file is convenient. I might switch over!
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I also rate the printer's performance as far more important. I have uncovered multiple issues leading to less than optimal quality for these newer Canon printers. When all the stars align, the dot pattern is ridiculously fine, better in some color regions than Epson OEM driver, and more consistent across the color range.
That sounds both good and bad: I take it what you mean is that it's really important to get everything set up right, and then the results are very good; but anything wrong could give poor (or at least sub-optimal) results.
I would certainly be interested in what you've found to be the key things that need to be done. Off the top of my head, from what I've learnt so far, I would have thought:
1. Paper with .am1 with spectral data
2. Head height and vacuum set correctly for this paper
3. Do head alignment on Canon HW Coated Genuine Paper (or good glossy paper) from time to time
4. Do a nozzle check on glossy paper (maybe not necessary?).
5. Do paper feed adjustment.
6. Calibrate paper using Unique calibration preferably, otherwise Common calibration is OK (do Common Calibration if calibration test shows that calibration has drifted beyond acceptable limit.
7. Profile paper with 2000+ patches (but possibly 1200 patches would be OK ... 2 A4 sheets would do this)
Anything else you would consider important?
Robert
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No problem Robert. I am happy to share what I know. It would be fantastic if you could run some of the tests yourself and report your findings. They might be different from my observations and I think we would both want to know why - and understand these printers better.
1. The plug-in supports 16 bits, but the on-board hardware may or may not quantize the bits to 12. Scott Martin said they did on the X1XX printers. (http://canonipf.wikispaces.com/Plugin+Bit+Depth) I don't know about the X4XX printers.
2. We could talk about this for weeks, it is such an interesting topic. Generally speaking, 2000+ patches (well distributed or well chosen sampling) is at the point of diminishing returns. You are safe here. With active calibration, the X4XX printers are very linear and actually need less patches to profile well. Like you, my preference is also to fill my chosen paper size with patches to reduce paper wastage.
3. I used ColorThink Pro for comparing my data. I just did a quick look at i1Profiler's Data Analysis function. It performs just as well. Being able to parse its own mxf measurement file is convenient. I might switch over!
1. So 16-bit is only available from the plug-in? Not if using the printer driver (on Windows, that is)? If the hardware knocks it down to 12 bits I wouldn't be too concerned, it would still be a lot better than 8 bits.
2. As I mentioned in my previous post, perhaps 1274 patches would be enough (2xA4 sheets for the i1Pro), seeing as how the printer is quite linear. Still, it would be leaving double the interpolation distance (I guess), so if we want very smooth gradients it might be best to go for the higher spot count.
3. Yes, i1Profiler looks OK. I haven't tried it yet, but what I have tried is a test using ArgyllCMS. It produces the Lab values for the two targets, delta E values (plain old dE, dE94 or dE2000), the worst, best, average, 10% and 90% best/worse and a vrml file that shows the differences visually (quite nice). What was interesting is that I got 3 values with dE2000 values of over 1, with an average of 0.33. And that's from prints done one after the other (could be some drying-time differences, I'll need to repeat the test).
If you're interested, here are the Argyll commands you would need:
targen -v -d2 -G -e8 -B8 -f400 chart1
printtarg -v -ii1 -a1.0 -T300 -M6 -pA4 chart1
copy chart1.ti2 chart2.ti2
copy chart1.tif chart2.tif
Pause print chart1.tif
chartread chart1
Pause print chart2.tif
chartread chart2
colverify -v2 -k -s -w -W -x chart1.ti3 chart2.ti3 > printerdrift.txt
You can then read the printerdrift.txt file into Excel with delimiter set to Space.
You can also use Argyll to check profile accuracy:
profcheck -v2 -k -w -x -p -Ir chart1.ti3 profile.icm
In this case the chart needs to be printed with the correct profile (so replace 'profile.icm').
Robert
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That paper is very thin and translucent and the black plastic of the platen would affect calibration to some extent, although in a consistent fashion. I'm not sure how it would affect calibration as I don't have any around to test against - I saw it only twice when Canon engineers brought it down for my printer repair. Actually, it would be great if you could test it against your Canson Photo Higloss paper and see what kind of differences you can measure.
Actually, I'm still wobbly about using a non-genuine Canon paper for common calibrations. For example, if I use the Canson HiGloss paper then I would have to put it in as GlossyPhotoHG255 (probably?), but the papers won't have the same white points, OBAs, spectral profiles, ink absorption etc. So it would seem to me that the chances are that the calibration wouldn't be the best. What do you think?
Your point about the thinness of the Glossy 170g is a good one ... I'll get one of the heavier papers.
Robert
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About reducing paper usage during calibration etc.
The printer will calibrate on one sheet of A4. For feed adjustment it requires 2 sheets of A4. Nozzle check 1 sheet of A4.
The feed adjustment and the calibration only uses part of the sheets, so they can be reused for ink level set/head height/vacuum strength adjustments.
So I reckon that for a new paper that I would need:
Calibration: 1 sheet
Feed adjustment: 2 sheets
Level settings: Re-use above
Profiling: 2-4 sheets (1292 - 2584 patches for i1Pro)
Assuming only 1292 patches this would require 630mm of 24" (leaving one spare A4) or 295mm of 44" papers. For 2584 patches we would need 840mm of 24" (again leaving 1 spare A4), or 590mm of 44" papers (leaving 3 spare A4 sheets).
I don't know how that compares to just using the rolls, but I image there is a good saving there (a calibration on 24" roll used 260mm of paper with most of the paper unused).
Robert
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How do you see the head height in mm? I only see Super Low, Lowest, Low, Standard, High and Highest.
samuel , it is the paper thickness i am referring to. I assume the head height is relative to the specified paper thickness. Like it is in the epson stylus pro printers.
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samuel , it is the paper thickness i am referring to. I assume the head height is relative to the specified paper thickness. Like it is in the epson stylus pro printers.
Hi JRSmit, thanks for clarifying. But I'm pretty sure I saw the head height names correspond to exact mm values somewhere...
Haha I found it! Service manual of the iPF8300, page 222 and 250.
Super Low - 1.2mm
Lowest - 1.4mm
Low - 1.8mm
Standard - 2.0mm
High - 2.2mm
Highest 2.6mm
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I'm still a bit concerned about the OBA side of things. I would have thought that unless the LEDs have no UV or that the densitometer has a UV filter, that the OBAs will affect the calibration: for example, the white will be bluer and brighter than it would be without UV. Perhaps that doesn't matter if we are profiling the papers, but it could make quite a difference if we use manufacturer-supplied profiles with common calibration (if we use manufacturer supplied profiles I would think that we should do a unique calibration on the paper).
I'm thinking that this whole thing is potentially quite messy, and the best thing is to use a common calibration using a paper that has minimal or no OBAs and always profile the papers.
Robert
Robert
It is unlikely that the iPF densitometer triggers a fluorescent effect from the OBAs, it would not correspond well with the common UV cut spectrometers that should create the iPFs profiles. The spectrometer of the HP Zs is UV cut as well in both calibration and profiling.
--
Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
September 2014, 650+ inkjet media white spectral plots.
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That sounds both good and bad: I take it what you mean is that it's really important to get everything set up right, and then the results are very good; but anything wrong could give poor (or at least sub-optimal) results.
I would certainly be interested in what you've found to be the key things that need to be done. Off the top of my head, from what I've learnt so far, I would have thought:
1. Paper with .am1 with spectral data
2. Head height and vacuum set correctly for this paper
3. Do head alignment on Canon HW Coated Genuine Paper (or good glossy paper) from time to time
4. Do a nozzle check on glossy paper (maybe not necessary?).
5. Do paper feed adjustment.
6. Calibrate paper using Unique calibration preferably, otherwise Common calibration is OK (do Common Calibration if calibration test shows that calibration has drifted beyond acceptable limit.
7. Profile paper with 2000+ patches (but possibly 1200 patches would be OK ... 2 A4 sheets would do this)
Anything else you would consider important?
Robert
Yes, that is right. It is also extremely helpful to know the optimal gamut behavior of the printer, so when something goes wrong, it is easy to catch it. Keep notes of your printer - it should be pretty ideal as it is new. Look very closely for micro banding issues too. Sometimes the auto adjustments are not perfect and needs to be done again. This happens when the paper is wavy or curled - varying the space between it and the print head.
1. Spectral data is not important. Don't forget that until the X4XX printers, this was never available, and people could still make excellent prints, as they can do now. I have not seen any evidence of spectral data providing any significant benefits to print output quality.
3. Head alignment should be done on your favourite paper - the distance from the paper to the print head is important. Thin matte papers are not ideal at all. If your favourite paper is a textured or matte paper, I would suggest aligning on a smooth glossy paper of equal thickness. I only run the alignment again when I notice issues with the dot placement precision, otherwise only when changing the print head or the entire carriage assembly, belt drive etc. I usually run the initial alignment if I have problems. I find it far more effective than the auto or manual alignments.
4. This is usually not necessary until you notice a problem like density loss, color drop outs, misfiring, color channel specific banding parallel to carriage travel etc. You can print this on any standard laser 80gsm paper.
5. I strongly recommend doing this on roll paper, if you are printing from a roll. It keeps the paper under a consistent tension, and the paper is flat across the width of the roll because the rest of itself is wrapped around. The portion over the platen will always lie at the same height to the print head. Cut sheets will always be somewhat wavy across their length and width, and this will affect the alignment. I have wasted a lot of paper to learn this!
6. Actually, calibrate using common calibration always. Unique calibration is an advanced user option, IMHO.
7. That is a bit simplistic, but ok for now.
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So 16-bit is only available from the plug-in? Not if using the printer driver (on Windows, that is)? If the hardware knocks it down to 12 bits I wouldn't be too concerned, it would still be a lot better than 8 bits.
Yes, 16 bits only with the plug-in. True, 12 bits is much better than 8 bits. But I would not mind having 16 bits.
I haven't tried it yet, but what I have tried is a test using ArgyllCMS. It produces the Lab values for the two targets
No recalibration in between?
What was interesting is that I got 3 values with dE2000 values of over 1, with an average of 0.33.
That is unnaturally high. I typically see average dE2k values of less than 0.1, and max of no more than 0.5. Measuring by hand with the i1 Pro 2 is not the most consistent method I'm afraid, but good technique should yield results of less than 1 de2k for the maximum deviation. If they were printed one right after the other and left to dry in the same location that should not play a significant role in the measurement difference.
Thanks for the argyllcms arguments. I'll look into it in more detail when I have the time. It's an excellent and lovely thing.
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So it would seem to me that the chances are that the calibration wouldn't be the best. What do you think?
Remember, the calibration routine is just a linearizing routine. It serves the nature of calibration only if you use the same paper, same setup and run the calibration function in the future. Calibrate on your favourite glossy media. I have done so with great success, and I am very fussy about my results.
EDIT: I'm with Ernst on this! I doubt the OBAs matter at all.
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No recalibration in between?
That is unnaturally high. I typically see average dE2k values of less than 0.1, and max of no more than 0.5. Measuring by hand with the i1 Pro 2 is not the most consistent method I'm afraid, but good technique should yield results of less than 1 de2k for the maximum deviation. If they were printed one right after the other and left to dry in the same location that should not play a significant role in the measurement difference.
No calibration in between ... so not too good! I'll scan the targets again and see if I messed up somewhere. But a dE2K of less than 0.1 I'm not expecting!
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About reducing paper usage during calibration etc.
Excellent, thanks for sharing. I will still stick with working with roll paper, for reasons I mention earlier. Much better material structural stability and height consistency. Also, unless you are very careful in handling and selecting cut sheets, you may potentially have scuffing in the printed areas. My own limited experience with cut sheets is that the smaller sheets have potentially more surface damage (less area to grab when packing them into boxes). These papers are very fragile. I notice that when calibrating from a roll, the printer will feed a great deal of paper out first before printing - but that ensures that it prints on the cleanest part of the paper that was never touched.
Feed adjustment should best be done on roll media. If you primarily print on sheets, use a single (very flat) sheet for doing the adjustment I feel is better.
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Remember, the calibration routine is just a linearizing routine. It serves the nature of calibration only if you use the same paper, same setup and run the calibration function in the future. Calibrate on your favourite glossy media. I have done so with great success, and I am very fussy about my results.
Yes ... I agree. The only thing is though that if you only do a common calibration then you really have to profile all the papers (can't use manufacturer profiles, for example). But as Geraldo says the Canson profiles are quite poor, reprofiling seems necessary anyway.
I'm coming at this from the HPZ3100 angle, where one always calibrates each paper ... and quite regularly too. Seems like the Canon printheads must be much more stable.
Robert
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Excellent, thanks for sharing. I will still stick with working with roll paper, for reasons I mention earlier. Much better material structural stability and height consistency. Also, unless you are very careful in handling and selecting cut sheets, you may potentially have scuffing in the printed areas. My own limited experience with cut sheets is that the smaller sheets have potentially more surface damage (less area to grab when packing them into boxes). These papers are very fragile. I notice that when calibrating from a roll, the printer will feed a great deal of paper out first before printing - but that ensures that it prints on the cleanest part of the paper that was never touched.
Feed adjustment should best be done on roll media. If you primarily print on sheets, use a single (very flat) sheet for doing the adjustment I feel is better.
As calibration seems to be something that's not needed very often, there's really not much advantage to using sheets. Multiple targets can be printed at the same time for profiling, of course, so again there's nothing to be gained from using sheet paper. For feed adjustment the printer uses 2 A4 sheets ... so might as well stick to roll again!
Things are getting a bit simpler in my head as I go along ... with a lot of help from you guys!
Robert
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1. Spectral data is not important. Don't forget that until the X4XX printers, this was never available, and people could still make excellent prints, as they can do now. I have not seen any evidence of spectral data providing any significant benefits to print output quality.
I forgot to mention that Canon is marketing the ability to perform color calibration-links across all the X4XX printers (not possible on all the older models) and I believe this is why the .am1 files supporting spectral data and unique calibrations were introduced. Without this, it would be impossible to get two or more printers to within 2 dE2k of each other. That's what they claim is possible. I think this is why I and Geraldo do not see any real improvement in print quality/accuracy with unique calibration. Basically because there is no improvement.
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The only thing is though that if you only do a common calibration then you really have to profile all the papers (can't use manufacturer profiles, for example). But as Geraldo says the Canson profiles are quite poor, reprofiling seems necessary anyway.
You have an i1 Pro 2 and i1Profiler and Argyll. You are in a good position to create far better profiles. Do it! :)
Seems like the Canon printheads must be much more stable.
I think so too. HP heads are the least consistent, Canon a bit more and Epsons are the most consistent.
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But epson heads are horrendously expensive to replace. :P
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Hi JRSmit, thanks for clarifying. But I'm pretty sure I saw the head height names correspond to exact mm values somewhere...
Haha I found it! Service manual of the iPF8300, page 222 and 250.
Super Low - 1.2mm
Lowest - 1.4mm
Low - 1.8mm
Standard - 2.0mm
High - 2.2mm
Highest 2.6mm
Based on this you would think that Super Low would be OK for everything except front-loading of boards. I see that the user manual recommends Automatic. The Canson Platine is less than 0.6mm thick, so a setting of Automatic should be OK I would have thought.
I noticed that the blue borderless printing switches were set to borderless ... could account for the scuffing at the sides of the paper I guess.
Robert
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I forgot to mention that Canon is marketing the ability to perform color calibration-links across all the X4XX printers (not possible on all the older models) and I believe this is why the .am1 files supporting spectral data and unique calibrations were introduced. Without this, it would be impossible to get two or more printers to within 2 dE2k of each other. That's what they claim is possible. I think this is why I and Geraldo do not see any real improvement in print quality/accuracy with unique calibration. Basically because there is no improvement.
It's good when things make sense :)
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You have an i1 Pro 2 and i1Profiler and Argyll. You are in a good position to create far better profiles. Do it! :)
Yes, for sure! I'm a bit spoilt for choice. I have no idea how one would compare the quality of the Xrite versus Argyll profiles. One thing that is almost definitely superior with the Argyll profiling is that it's possible to generate image-specific profiles: which can improve Perceptual mapping a whole lot (particularly if one is printing from a very wide working space like ProPhoto to a small gamut destination like a matte paper). But it's one of these quite time-consuming (but easy to do) operations as the profile has to be generated for each image. On the other hand, if there was a batch of images one could just kick off the profiling and go and have a sleep and the profiles would all be ready when you woke up :).
Robert
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But epson heads are horrendously expensive to replace. :P
What is the price when buying a head from Epson?
Canon is now recommending users replace both printheads every year, at the cost of some $1000 a year. I don't think it is any cheaper over time.
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Based on this you would think that Super Low would be OK for everything except front-loading of boards.
Robert, some problems here. You are going to be damaging your carriage and print heads prematurely if you set it that low all the time.
Have a look first at which media settings support super low head height - not all do.
The paper may be thin enough to fit under the head, but due to various factors like paper not lying flat, curl from roll, humidity, ink load etc, it will bulge higher than usual. I'm also not confident that the lowest point of the carriage is always exactly 1.2mm over the platen.
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Yes, for sure! I'm a bit spoilt for choice. I have no idea how one would compare the quality of the Xrite versus Argyll profiles. One thing that is almost definitely superior with the Argyll profiling is that it's possible to generate image-specific profiles: which can improve Perceptual mapping a whole lot (particularly if one is printing from a very wide working space like ProPhoto to a small gamut destination like a matte paper). But it's one of these quite time-consuming (but easy to do) operations as the profile has to be generated for each image. On the other hand, if there was a batch of images one could just kick off the profiling and go and have a sleep and the profiles would all be ready when you woke up :).
Robert
That is something I have been meaning to test. The perceptual rendering from i1Profiler is fantastic mostly. I would love to see if it can be bettered.
You test profile quality the same way you have been testing your profile conversions with Bill's balls and Andrew's picture. Plus make some prints. A lot of prints. Soft proofing helps a lot to catch the main behavior without wasting too much paper and time. Color geek software can be useful to provide some quantification of your results. You have posted a lot on that; I believe you know what to look out for, the usual suspects. It is nice to know the behavior of the various profiling engines, but no one is publishing this information, and it is ridiculously time consuming and expensive to test. I have been doing a lot of that last year, but i1Profiler has updated their color engine again.
Funnily enough, softproofing in Photoshop is not very precise but I don't know why no one has pointed it out before. Soft proofing in the Canon 16 bit plug-in is more accurate. Often I would see gradients soft proof as smooth in Photoshop, but print with slight banding. Sometimes there is tone and color shifts not present in the actual prints. Soft proofing in the Canon plug-in shows the banding, and the correct rendering of tone and color. There are other issues too, but that is a whole different topic...
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About 2-3K per head replacement. And the capping station needs to be replaced along with the head, plus the ink needed to prime the new head. Ouch.
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That is something I have been meaning to test. The perceptual rendering from i1Profiler is fantastic mostly. I would love to see if it can be bettered.
You test profile quality the same way you have been testing your profile conversions with Bill's balls and Andrew's picture. Plus make some prints. A lot of prints. Soft proofing helps a lot to catch the main behavior without wasting too much paper and time. Color geek software can be useful to provide some quantification of your results. You have posted a lot on that; I believe you know what to look out for, the usual suspects. It is nice to know the behavior of the various profiling engines, but no one is publishing this information, and it is ridiculously time consuming and expensive to test. I have been doing a lot of that last year, but i1Profiler has updated their color engine again.
Funnily enough, softproofing in Photoshop is not very precise but I don't know why no one has pointed it out before. Soft proofing in the Canon 16 bit plug-in is more accurate. Often I would see gradients soft proof as smooth in Photoshop, but print with slight banding. Sometimes there is tone and color shifts not present in the actual prints. Soft proofing in the Canon plug-in shows the banding, and the correct rendering of tone and color. There are other issues too, but that is a whole different topic...
Yes, Andrew's balls can be of some use for this sort of test alright. Still - it ends up being very specific and in the case of the balls we're dealing with 100% saturated colors in ProPhoto, so using an intelligent mapping isn't going to be much better than using the CMM (if at all). The real benefit will be when using a workspace like ProPhoto, but with colors that are not too far out of the destination gamut.
I think i1Profiler uses a combination relative/perceptual mapping for the perceptual mappings, possibly with colors not too far out of gamut being mapped perceptually and colors well out of gamut being mapped colorimetrically ... or something along those lines. It's entirely up to the profile maker what sort of algorithm to use and unfortunately XRite don't tell us how they do their perceptual mappings.
I'm not sure if I posted this elsewhere, but here is a Perl script to do the perceptual mapping using Argyll (call the script perceptual.pl):
use strict;
use warnings;
my $inprofile = $ARGV[0];
my $outprofile = $ARGV[1];
my $intiff = $ARGV[2];
my $outtiff = $ARGV[3];
my $gam = $intiff; $gam =~ s/\.tif*$/.gam/; my $linkprofile = $intiff; $linkprofile =~ s/\.tif*$/.icm/;
print "Creating Gamut file\n";
#`tiffgamut -v -f90 -w -pj \"${inprofile}\" \"${intiff}\"`;
`tiffgamut -v -w -pj \"${inprofile}\" \"${intiff}\"`;
print "Making Link File\n";
`collink -v -dmt -qm -G\"${gam}\" -ip \"${inprofile}\" \"${outprofile}\" \"${linkprofile}\"`;
`del "${gam}\"`;
print "Making Perceptual TIF Image: ${outtiff} with embedded profile\n";
`cctiff -e \"${outprofile}" \"${linkprofile}\" \"${intiff}\" \"${outtiff}\"`;
#print "Making Perceptual TIF Image: ${outtiff} WITHOUT embedded profile\n";
#`cctiff \"${linkprofile}\" \"${intiff}\" \"${outtiff}\"`;
You can call this script in Windows with this batch file (call the batch file perc.bat):
rem Convert image from source to destination using an intelligent perceptual mapping.
rem Parameter 1 is the source profile (for example ProPhoto). The profile extention must be .icc (do not specify it)
rem parameter 2 is the destination profile (for example HPZ3100-CansonPhotoHiGloss). The profile extention must be .icc (do not specify it)
rem Parameter 3 is the image name. It must be a tif image. Do not specify the extension
rem Example: 'perc ProPhoto PZ3100-CansonPhotoHiGloss testImage'
rem the converted image will be called 'imageName-perc-destinationProfile.tif'
perl perceptual.pl %1.icc %2.icc %3.tif %3-perc-%2.tif
The script takes around 2 minutes on my PC, so it's not exactly quick, but it does a lot of processing!
Robert
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What is the price when buying a head from Epson?
Canon is now recommending users replace both printheads every year, at the cost of some $1000 a year. I don't think it is any cheaper over time.
That's brutal! How much ink are the heads rated for, do you know? The HP heads are rated at something like 2 litres per color, so you would need to be doing a lot of printing to have to replace the heads every year. Do you know why the recommendation? Is it just to a handy way to make more money, or is there a genuine technical reason, beyond ink clogging?
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from: samueljohnchia on October 15, 2014, 08:30:30 PM
What is the price when buying a head from Epson?
Canon is now recommending users replace both printheads every year, at the cost of some $1000 a year. I don't think it is any cheaper over time.
I came across this on the iPF wiki:
Printheads are expensive ($450-500 each, current street price; two printheads in a printer) and each one comes with a warranty of one year or when the status of the internal dot counter changes from "a" to "b", whichever comes first. Since the internal dot counter used to verify the warranty validity does not indicate actual dot count, users cannot reliably estimate how much warranty period is left. Canon only gives an estimate of the amount of ink used before the warranty expires--4,000 ml per printhead. This volume does not include ink used for maintenance. This may be particularly significant for those who do not print a lot, as their warranty could expire after one year when they have not printed a high volume of work. Note that the warranty covers approximately 40% of the "expected printhead life", so the average expected throughput is about 2.5 times this amount (according to Canon document on their web site). In addition, the Canon extended warranty does not cover printheads as the Epson extended warranty does. There are only a few reports so far of early printhead failure, and all were covered by Canon under warranty.
I also came across this Canon document http://canonipf.wikispaces.com/file/detail/ExpectedPrintHeadLifeGuideline.pdf which indicates between 7000 and 14000 prints as the printhead life for PF-01/02/03 heads.
So it would seem that we should hopefully get something over 1600ml per color before seeing a head failure (12-14 130ml ink cartridges or 5-6 300ml cartridges). Of course this could be just on one color, like the light gray. At any rate, certainly a lot more than I would use in a year ... more like 6 years in my case!!
Robert
Robert
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About 2-3K per head replacement. And the capping station needs to be replaced along with the head, plus the ink needed to prime the new head. Ouch.
So that's basically the same cost as the Canon heads in the long run... :(
Canon uses 17 grams of ink per color channel to prime the new heads. About $50 of ink per head change.
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Do you know why the recommendation?
I was told that old heads have many clogged nozzles in them, which cause over heating and then shorts out vital electrical components. But that just sounds like a wonky explanation to me. Canon printers have never been good in terms of their electronics. Why should a print head take out a $3000 mainboard? So at the end of the day you can ask yourself, would you like to replace 6 heads over 3 years for $3000, or one mainboard in three years at $3000?
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At any rate, certainly a lot more than I would use in a year ... more like 6 years in my case!!
Yes, the wiki has the right information. But if you are a low volume user, you might find that you are replacing heads sooner than expected. You certainly won't get that much ink through them before they die.
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Yes, the wiki has the right information. But if you are a low volume user, you might find that you are replacing heads sooner than expected. You certainly won't get that much ink through them before they die.
I might have stuck with a Z3200 if I had known ... the Z3100 I had was still running without a single channel block after 6 years and I didn't once run a nozzle clean.
I guess we live and learn.
Robert
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Hi,
Here is a useful set of commands that can be used with ArgyllCMS to check to see how good your print system is:
targen -v -d2 -G -f100 iPFTest
copy iPFTest.ti1 iPFRef.ti1
printtarg -v -r -ii1 -a1.0 -T300 -M6 -pA4 iPFTest
cctiff -v -ir -e iPF6400_HP_ID_Satin.icm iPFTest.tif iPFTestO.tif
move /Y iPFTestO.tif iPFTest.tif
fakeread -v -Ir iPF6400_HP_ID_Satin.icm iPFRef
Pause Print iPFTest.tif using no color management
chartread iPFTest
Pause The test results will be in iPFValidate.txt
colverify -v2 -N -k -s -w -x iPFRef.ti3 iPFTest.ti3 >iPFValidate.txt
The -f flag in the targen command defines the number of patches in the test chart. Obviously you would need to change the profile to the correct profile for your paper (that is, from iPF6400_HP_ID_Satin.icm to whatever profile you are using.
The commands do the following:
- targen defines a test chart (iPFTest in this case) with the number of patches specified (100 in this case)
- printtarg generates the .tif file to be printed (set up for an i1Pro/2 with A4 paper)
- cctiff converts the test chart file to the target profile, ready for printing
- fakeread simulates the reading of the test chart, as though it had been printed using the icc profile
- chartread reads the printed chart
- colverify compares the scanned data from the printed chart to the simulated chart read from fakeread
If the printer was perfectly calibrated and the profile totally current for the paper, the results of the test (which will be in the file iPFValidate.txt) will show very low delta E values. For example, in a test I just did, the worst dE value was well under 1. If the printer calibration had drifted, or if a new roll of paper was used, then the results would give a very good indication of whether or not the paper should be reprofiled.
The test does not tell you how good the profile is.
I hope this may be of use.
Robert
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I might have stuck with a Z3200 if I had known ... the Z3100 I had was still running without a single channel block after 6 years and I didn't once run a nozzle clean.
The Canons are supposed to work more or less the same way. The print head technology was invented by Canon for what its worth. Your HP certainly runs nozzle 'cleans' on its own, even if you do not initiate it. The Canon printers do the same. If all goes well, one shouldn't run a nozzle clean. I have heard of at least one user on the ipf wiki saying he was still on his original print head on the iPF5000, also about 6 years IIRC. Others have had theirs fail right out of the box. There was an early batch problem with the PF-05 heads, bad right out of the box or very early failures. Canon has gone through 3 revisions of that head. Hopefully yours will last a long time!
I personally won't bother with changing them every year though. Just use them until the printer tells you to change.
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Hi,
Here is a useful set of commands that can be used with ArgyllCMS to check to see how good your print system is:
Thanks Robert, I'm saving notes of all your ArgyllCMS related information.
It is excellent to know that you are seeing values far less than 1 dE. What is the actual dE report, with a break down of the best, worst and average measurements?
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Thanks Robert, I'm saving notes of all your ArgyllCMS related information.
It is excellent to know that you are seeing values far less than 1 dE. What is the actual dE report, with a break down of the best, worst and average measurements?
Hi Samuel,
I didn't keep the results from the last test, so I redid the test and the results are not quite as good this time, but still very good:
Total errors (CIEDE2000): peak = 1.049735, avg = 0.528698
Worst 10% errors (CIEDE2000): peak = 1.049735, avg = 1.053080
Best 90% errors (CIEDE2000): peak = 0.867472, avg = 0.480072
avg err: X 0.003830, Y 0.003735, Z 0.002949
avg err: L* 0.476939, a* 0.415635, b* 0.417006
This is a test on an HP Instant Dry Satin paper on the iPF6400. I wasn't over-careful with the profile (didn't leave much drying time for example) and used only 1200 patches; but it still shows that using Common Calibration is absolutely fine. I based the paper on the Canon Satin Photo 240. I'm very satisfied with this.
Robert
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Hi Robert,
Just to make sure I understood it correctly, you calibrated your printer using HP instant dry satin paper and the Canon Satin Photo 240 media setting, then built a 1200 patch profile.
Did you
1. re-calibrate the printer then print a second 1200 patch target and verified it against the profile by letting ArgyllCMS simulate the measurement
2. You did not re-calibrate and just printed a second 1200 patch target and verified it against the profile?
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Hi Robert,
Just to make sure I understood it correctly, you calibrated your printer using HP instant dry satin paper and the Canon Satin Photo 240 media setting, then built a 1200 patch profile.
Did you
1. re-calibrate the printer then print a second 1200 patch target and verified it against the profile by letting ArgyllCMS simulate the measurement
2. You did not re-calibrate and just printed a second 1200 patch target and verified it against the profile?
Hi Samuel,
I know it's a bit confusing, but I'll try to explain it as well as I can :).
First of all, I calibrated the printer using the Canon HW Coated paper (it's the only Canon paper I currently have ... I'm just waiting for some to arrive). The iPF6400 comes with 5 sheets of A2 HW Coated for printhead alignment (and, I assume, common calibration) ... not a lot!
Then I created a new custom paper using the HP Instant Dry Satin paper and based it on the Canon 240gsm Satin paper. I did a paper feed adjustment etc.
Then I created an icc profile for the paper using 1292 patches using i1Profiler on the same roll of HP ID Satin.
I did some test prints and everything seemed fine.
Now on to Argyll.
What I did there (this is in the commands I posted) is to create a 100 patch target and converted it to the profile I had created for the paper before printing it using no color management (I could have left the paper with no color profile and printed it with the profile instead of no color management, but I'm not sure what the CMM would do in that situation as it has no source profile to work from). I scanned the printed target using the i1Pro2 and Argyll: this creates a .ti3 file.
The commands also simulate this process by converting the same 100 patch target to another .ti3 file, through the icc profile (that's the fakeread command). It's simulating the print and scan and so it represents the ideal situation of a perfect print ... as it's all software and there's no real paper or printer involved.
So by comparing the two .ti3 files we can see how close to ideal the print and scan are. In the case of the ID Satin it's really very close with an average dE2000K error of 0.5, which most of us couldn't distinguish (and which may not be far off the resolution of the i1Pro2).
What that proves to me is that calibrating the printer using a common calibration is just fine (as you and Geraldo have said to me) and there's really no need to be worrying about .ac1 files and spectral data etc. It also shows that i1Profiler did a very good job of profiling the printer (because if it had not then the dE figures would be way out).
What it doesn't say much about is how good the profile is in terms of smoothness, for example. I would think not very good because I only used around 1200 patches (Graham Gill of Argyll recommends 3000+ patches for a high quality inkjet RGB profile).
The other thing that's useful with this test is that if you run it today and note the results, then run it again in a month's time (or after you've changed the roll for a new one, say, or put in a new ink cartridge) then if the results of the new test are significantly worse than the first it's telling you that you need to reprofile the paper. It's very easy to automate this as the text file can be converted to an Excel spreadsheet easily (you just need to cut and paste it into Excel, global remove all the ':', and convert text to columns with space as the delimeter). So you do this with the first set of values and then with the second set of values and you can then compare the two sets very easily.
Argyll seems quite daunting at first because it's all command-line stuff, but once you have some batch files it becomes very easy. You just need to download the software which you can get for free here: http://www.argyllcms.com/. It supports most spectros like the ColorMunki, i1Pro etc., as well as most colorimeters. The documentation is also very good and it's easy to get help.
I don't know how the Argyll-generated profiles stack up compared to i1Profiler ... that's altogether a more difficult thing to establish. i1Profiler is nice and visual ... Argyll has many advanced options. My feeling is that probably one is better at some things and the other better at others ... but for me at this stage I would tend to use i1Profiler to make profiles because it's easier, but I would use Argyll for the sort of test that we're talking about and also if I needed a particularly good perceptual rendering for an image, as only Argyll can do an optimised perceptual render.
Robert
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What that proves to me is that calibrating the printer using a common calibration is just fine (as you and Geraldo have said to me) and there's really no need to be worrying about .ac1 files and spectral data etc. It also shows that i1Profiler did a very good job of profiling the printer (because if it had not then the dE figures would be way out).
Robert, Thank you for detailing your process. I understand now. Yes, common calibration works alright, but unfortunately your test does not prove that common calibration works well - it merely proves that i1Profiler did a good job (correct on that one) and that your measurement by hand is ok.
To prove that common calibration works ok, you should run calibration again, and the compared the measurement data of the first target to the second target - no profile involved at all. No fakeread with Argyll. Just compare only the measurement data. The only variable is the repeatability of the i1 Pro 2, which can be reasonably good if your technique is excellent when measuring by hand.
I did just that with the iSis, multiple measurements, extra large patches sizes, to minimize measurement errors. I had good results as I reported earlier.
In the case of the ID Satin it's really very close with an average dE2000K error of 0.5, which most of us couldn't distinguish (and which may not be far off the resolution of the i1Pro2).
If you measure the same target twice and you are seeing these numbers, something would be wrong - I would look into whether measurement technique can be improved, paying attention to issues like your dragging speed, consistency of speed, ruler position, measurement aperture position. Maybe the patches are on the limit of the minimum patch size for the device, increasing the patch width could help. The average dE2K of the i1 Pro 2 is about 0.1 - 0.15 when remeasuring. Because you did not do that it is hard to say what else might be contributing to the errors.
This old topic (http://www.luminous-landscape.com/forum/index.php?topic=27408.0) is a good reference of what you should be seeing with the respective devices.
What it doesn't say much about is how good the profile is in terms of smoothness, for example. I would think not very good because I only used around 1200 patches (Graham Gill of Argyll recommends 3000+ patches for a high quality inkjet RGB profile).
Yes, you could certainly go with a larger amount of patches. Around 2000 (well chosen) patches or so is the point of diminishing returns. Having 3000+ patches increases the risk of measurement errors significantly. Try measuring the same target two or three times and you might notice just how different the measurements can be. Part of that is user error, part of that is software limitations to derive the measurement data.
Argyll seems quite daunting at first because it's all command-line stuff, but once you have some batch files it becomes very easy.
Yes, I agree! I have used Argyll a number of times. I don't have any experience with batch files and scripting but I must look into it when I have time. Argyll does some things better than i1Profiler, and vice versa. But it is quite hard to beat i1Profiler's perceptual rendering when it is set up optimally. I have made tests which show other profiling solutions offering better results in some cases, but the question is which is the best overall? Won't it be great to combine all the best qualities of each?
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Robert, Thank you for detailing your process. I understand now. Yes, common calibration works alright, but unfortunately your test does not prove that common calibration works well - it merely proves that i1Profiler did a good job (correct on that one) and that your measurement by hand is ok.
To prove that common calibration works ok, you should run calibration again, and the compared the measurement data of the first target to the second target - no profile involved at all. No fakeread with Argyll. Just compare only the measurement data. The only variable is the repeatability of the i1 Pro 2, which can be reasonably good if your technique is excellent when measuring by hand.
What I meant when I said that Common Calibration works OK is that it is not necessary to have a .am1 media file with spectral data in order to get accurate print results; it's quite enough to use Common Calibration as the profiling handles the less than perfect calibration that one would expect when using Common Calibration.
But yes, it does also say that i1Profiler did a good job of profiling.
If you measure the same target twice and you are seeing these numbers, something would be wrong - I would look into whether measurement technique can be improved, paying attention to issues like your dragging speed, consistency of speed, ruler position, measurement aperture position. Maybe the patches are on the limit of the minimum patch size for the device, increasing the patch width could help. The average dE2K of the i1 Pro 2 is about 0.1 - 0.15 when remeasuring. Because you did not do that it is hard to say what else might be contributing to the errors.
I haven't done a repeated test with the i1Pro so I'm not sure what the repeatability is. I'll check that out when I have some time. But you have to remember that the dE errors I'm showing here are the differences between an actual print and the ideal ... to get an average dE of 0.5 with a max of 1 is pretty damn good! My comment about the resolution of the i1Pro was not warranted (although, looking at the link you gave me it would seem that a max dE2000K of around 0.5 with a manual scan might not be unexpected).
This old topic (http://www.luminous-landscape.com/forum/index.php?topic=27408.0) is a good reference of what you should be seeing with the respective devices.
Yes, you could certainly go with a larger amount of patches. Around 2000 (well chosen) patches or so is the point of diminishing returns. Having 3000+ patches increases the risk of measurement errors significantly. Try measuring the same target two or three times and you might notice just how different the measurements can be. Part of that is user error, part of that is software limitations to derive the measurement data.
Yes, I agree! I have used Argyll a number of times. I don't have any experience with batch files and scripting but I must look into it when I have time. Argyll does some things better than i1Profiler, and vice versa. But it is quite hard to beat i1Profiler's perceptual rendering when it is set up optimally. I have made tests which show other profiling solutions offering better results in some cases, but the question is which is the best overall? Won't it be great to combine all the best qualities of each?
How do you set up i1Profiler to give an optimal result for a Perceptual profile?
Thanks for the info!
Robert
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Hi Samuel,
I tested the i1Pro2 against a 100 spot wedge (scanned twice with a calibration in between) and as you can see below the dE2000 are better than 0.3, with an average of .06, which seems pretty OK.
===========================================================
Total errors (CIEDE2000) peak = 0.288437, avg = 0.064116
Worst 10% errors (CIEDE2000) peak = 0.288437, avg = 0.188102
Best 90% errors (CIEDE2000) peak = 0.115421, avg = 0.051622
avg err X 0.000583, Y 0.000591, Z 0.00044
avg err L* 0.053047, a* 0.042422, b* 0.063142
===========================================================
I also did a repeated spot-test on a single spot and got a peak dEab of .12 with an average of .04 over 25 readings (I had to calculate the dE values in Excel and dE2000 is too complicated for me ... it would need a VBA script probably, or a very complicated formula). The dE2000 values should be much lower that the dEab values, so that's very repeatable with a low error.
Robert
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What I meant when I said that Common Calibration works OK is that it is not necessary to have a .am1 media file with spectral data in order to get accurate print results; it's quite enough to use Common Calibration as the profiling handles the less than perfect calibration that one would expect when using Common Calibration.
Yes, it is not necessary to have spectal data and perform unique calibration to get accurate print results. But from your testing procedure, you could not conclusively make this statement.
If you didn't even run common calibration at all (you can turn it off on the printer), you would get equally good profiling results from the printer because it is new. Not that I recommend doing it this way.
Btw I've found your list thread about using fakeread on Argyll. Ben has given you excellent advise, I note.
the dE errors I'm showing here are the differences between an actual print and the ideal ... to get an average dE of 0.5 with a max of 1 is pretty damn good! My comment about the resolution of the i1Pro was not warranted (although, looking at the link you gave me it would seem that a max dE2000K of around 0.5 with a manual scan might not be unexpected).
Quite the opposite, if we are talking about device consistency, not profile accuracy. An average dE of 0.5 is huge and 5 times out of the specifications of the device. A max of 1 is quite bad also. I would run an i1diagnostics test in this situation and send in my i1 Pro for repair if it fails.
I'm still not convinced that it is the best way to validate profiles. I need to understand the inner workings of it better. I'll be snooping around. I think the error may also have something to do with the way fakeread interpolates the results for sampling points between the discrete points in the profile's CLUT.
I tested the i1Pro2 against a 100 spot wedge (scanned twice with a calibration in between) and as you can see below the dE2000 are better than 0.3, with an average of .06, which seems pretty OK.
This is not merely ok, it is really excellent! If you can keep up this level of measurement consistency when measuring 3000 patch profiling target, I bow to you sir.
I also did a repeated spot-test on a single spot and got a peak dEab of .12 with an average of .04 over 25 readings...so that's very repeatable with a low error.
Yes that's within the device specifications. All good.
How do you set up i1Profiler to give an optimal result for a Perceptual profile?
As a starting point, version 2 profile, D50, and zero all the profile settings sliders. Play around with the saturation and neutralize gray sliders depending on the media you are profiling, and what you are printing.
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Yes, it is not necessary to have spectal data and perform unique calibration to get accurate print results. But from your testing procedure, you could not conclusively make this statement.
If you didn't even run common calibration at all (you can turn it off on the printer), you would get equally good profiling results from the printer because it is new. Not that I recommend doing it this way.
Btw I've found your list thread about using fakeread on Argyll. Ben has given you excellent advise, I note.
Quite the opposite, if we are talking about device consistency, not profile accuracy. An average dE of 0.5 is huge and 5 times out of the specifications of the device. A max of 1 is quite bad also. I would run an i1diagnostics test in this situation and send in my i1 Pro for repair if it fails.
I'm still not convinced that it is the best way to validate profiles. I need to understand the inner workings of it better. I'll be snooping around. I think the error may also have something to do with the way fakeread interpolates the results for sampling points between the discrete points in the profile's CLUT.
The test procedure checks an actual print through the icc profile to a simulated print through the same icc profile. The simulated print has none of the printer/paper issues, it just takes the print wedge and produces the test data. So you can think of it as printing using a perfect printer. The comparison of the scanned print to this simulated print then tells you how well the printer/profile has performed. A max dE2000 of 1 with an average dE of 0.5 is excellent IMO: it means that if you viewed the print against an ideal print that you would not be able to tell the difference between them (or maybe JUST, on the few patches at around 1).
The printer calibration is a bit of a red herring because the profile will compensate for a poor calibration. It's just that it's better to have a calibrated printer so the profile has less of a job to do. What is very important though is making sure the printer is laying down the correct amount of ink. Have you found a good way of setting this ... using the media configuration tool, I assume?
So I think the test tells you the following:
- the print is producing Lab values that correspond very closely to the image values (rendered by the profile)
- the profile is OK - because if it was not the print values would be wrong.
- the printer is performing correctly - because if it was not the print values would be wrong.
- there is (or isn't) a current need to reprofile the paper
subject to these being only accurate to the extent that the print wedge is representative of the color gamut of the paper. This can be improved by using a wedge with more spot colors and also by tuning the targen parameters.
What the test does not tell you, IMO is the following:
- it doesn't tell you if the profile is smooth and was made with enough sample points
- it doesn't tell you how good the profile's rendering algorithm is - for example how well it has brought out-of-gamut colors into gamut and what it has done with the in-gamut color
- whether or not the printer has been properly calibrated
- whether or not the print ink limits are high enough or too high
So I think it's a very useful test, but it doesn't give you the full picture. To validate the profile fully is another day's work really ... and probably has to be done by examining test prints to see how smooth the rendering is, and so on.
A variation on the test is possible: and that is to compare the print scanned results to the actual image Lab values. But I think analyzing this would be very difficult because, after all, the profile's job is to alter the image colors to make them fit in a pleasing way into the print gamut, so there should be differences. But if we do this test making sure that all the image colors are within the print gamut then the values should be very close, so it may tell us something about the profile (would have to try it out to see what!).
Yes, Ben usually does give good advice ... although in this case I wouldn't quite agree with him: I think this is a useful test, easy to do, and one that can certainly point out a few potential problems that could end up saving a lot of time and wasted prints.
As a starting point, version 2 profile, D50, and zero all the profile settings sliders. Play around with the saturation and neutralize gray sliders depending on the media you are profiling, and what you are printing.
Thanks!
Robert
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The Canon Photoshop Print Plugin has the 300ppi setting grayed out. Is this because the plugin will resample to 600ppi anyway before printing, even if the image resolution is below that? If so it seems odd that there should be a 300ppi setting at all (grayed out or not).
Also, with Print Mode set to Highest (Maximum Number of Passes), is the dithering at 1200dpi?
Have you seen any difference between upsizing to 600ppi or just passing the 300ppi image to the plugin?
Thanks
Robert
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Robert, I don't think the test is as useful as you describe. Since the target's values are taken on the round trip through the profile, it is extremely unlikely that your measurements would be any different if you printed the same target right after profiling, like you did. Why should it be? Yes, I more or less agree with your list if your measurements are within 1dE2k of the "ideal" given by Argyll. But what if it is not? How would it tell you what has gone wrong? You would not know if it was a profile issue or a printing issue. Much better would be to print a "reference" target, ensure that you measured it properly, and keep your measurement data and the print. Then re-prints of the target in the future can be compared to this target, visually and measurably.
I think why you are measuring a difference of as large as 1dE and a relatively high average of 0.5 is due to the less than perfect simulation. These numbers are within the i1 Pro's specifications of device to device consistency. It may be that your i1 Pro differs from Argyll's by that much.
You are right that a good calibration is important so the profile does not bear all the heavy lifting. They work much better when the printer is more linear in its native state. Making sure the printer is laying down the right amount of ink should be the paper manufacturer's job - they build the .am1 files which contain this information. Unfortunately I do not find their choices of base media setting and inking always optimal, and I suspect that their spectral data, if created, was not done properly, so I create my own using the Media Configuration Tool. Depending on how fussy you are you can go down this route. Be prepared to spend a lot of time, ink and paper.
A variation on the test is possible: and that is to compare the print scanned results to the actual image Lab values.
Maybe www.colorcheck-online.de/ (http://www.colorcheck-online.de/) might be of interest to you.
The Canon Photoshop Print Plugin has the 300ppi setting grayed out.
This depends on the media setting selected. Try plain paper for example, you will see it available. If 600 ppi is selected, then the plug-in expects images of that resolution, otherwise it will resample it.
Also, with Print Mode set to Highest (Maximum Number of Passes), is the dithering at 1200dpi?
No, dithering does not occur at a fixed number of dpi. The output has a fixed droplet size and achieving lighter colors requires fewer dots spaced futher apart. 1200 dpi is the printer specification for the nozzle pitch. When max no. of passes is invoked, the ink order and layering changes, and the output is visibly smoother. 16 passes vs 7 passes compared to Highest.
Have you seen any difference between upsizing to 600ppi or just passing the 300ppi image to the plugin?
Yes of course. As always, hand over to the driver/plug-in images at the requested ppi, sharpened properly.
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Robert, I don't think the test is as useful as you describe. Since the target's values are taken on the round trip through the profile, it is extremely unlikely that your measurements would be any different if you printed the same target right after profiling, like you did. Why should it be? Yes, I more or less agree with your list if your measurements are within 1dE2k of the "ideal" given by Argyll. But what if it is not? How would it tell you what has gone wrong? You would not know if it was a profile issue or a printing issue. Much better would be to print a "reference" target, ensure that you measured it properly, and keep your measurement data and the print. Then re-prints of the target in the future can be compared to this target, visually and measurably.
I think why you are measuring a difference of as large as 1dE and a relatively high average of 0.5 is due to the less than perfect simulation. These numbers are within the i1 Pro's specifications of device to device consistency. It may be that your i1 Pro differs from Argyll's by that much.
Hi Samuel,
Thanks for the other info!
I think we should really start another topic for this discussion as it's quite interesting from a profiling/ color management point of view.
Anyway, here is my understanding of what the test is doing:
(http://www.irelandupclose.com/customer/LL/colverify.jpg)
First of all, the test target is copied, along with the patch definition to make the reference.
The test image is then printed through the profile and scanned to produce the test Lab values (as shown on the left hand path of the image)
The reference image is passed through Fakeread, which renders the image through the profile, just like the printing does, and it then converts the RGB values to Lab. It doesn't do a round-trip conversion, but it simulates the scan ... as it says in the documentation: fakeread ... "Simulates the measurement of a devices response". In other words it simulates the scan of the print.
The two sets of data are then compared using colverify.
Of course I could well be wrong, but my understanding of this process is that the simulation essentially removes the physical print and scanning with a spectro, so that it produces data that is ideal data, as if from a perfect printer and scanner. The comparison then should show the imperfections in the print/scan.
Most of the imperfection will be in the print because the spectrometer is very accurate (from my test I'm getting an average dE00 of 0.06 with a peak of better than 0.3). The comparison of the test v reference I did shows an average dE of about 0.5 with a peak of around 1. So the error due to the print+scan should be around 0.5+/- 0.06 average and 1+/-0.3 peak. There may be some small errors in the simulation (fakeread) but these would only be rounding-type errors which I would think are not significant.
Of course my understanding/interpretation could be wrong.
If we assume that it isn't wrong then what the test tells me is that the print is correct as per the profile. If I ran the test immediately after profiling the paper and the dE differences were large then it might mean that the profile was bad, or it might mean that something had gone wrong with the printer. It wouldn't tell me what was wrong but it would tell me that something was wrong ... so I would then have to investigate further.
If the comparison was OK immediately after profiling but was not after some time had passed, then I would know that the problem was most likely with the printer, and most likely with calibration drift. So then I would re-profile the paper.
Of course we could print & scan, then print & scan at a later stage and compare the two sets of data ... and these would equally well tell us if there was a need to reprofile.
So (again, if I understand the test correctly) it's not a magic bullet or a cure-all, but it's a useful test and it's also very easy to run because all that's required is to print the target and scan it and the commands do the rest.
Robert
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Maybe www.colorcheck-online.de/ (http://www.colorcheck-online.de/) might be of interest to you.
Thanks - this seems interesting. It isn't clear to me if the comparison is between the target printed using the print profile, against the Lab values of the reference, or whether the print profile is used so that the comparison is like the test I have here (that is, both fed through the profile). Do you know?
The problem with comparing the printed target through the icc profile to the Lab values of the reference is that the data will necessarily be different, especially for out-of-gamut colors. So how do you know then if the dE differences are normal and correct, or if they are an error?
This sort of testing can also be done with Argyll (supplemented with Excel for the graphs) ... unfortunately Argyll is complicated and has many options, which makes it hard to use (but very powerful if you know how to!); and even though there is help from the freelist forum it's patchy and slow. On the other hand, the ColorCheck-online seems quite easy and has some nice reporting ... but you have to pay for it and you get what they give you and have little control over what that is (I assume, not having tried it yet). The documentation being in German doesn't help (me anyway).
Robert
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Hi Robert, feel free to start another topic if you wish, although it seems we are having our own conversation here. I suspect that most of this information is much too esoteric and most cannot be bothered to set up their printing environment to such a particular level of detail.
Most of the imperfection will be in the print because the spectrometer is very accurate
Two problems here. One is that the spectrophotometer is not "accurate". In your one off test, it appears to be very consistent. A device can be consistently inaccurate if you know what I mean, like a ruler with an inaccurate scale. The i1 Pro varies from device to device by 0.4dE2k on average according to X-rite, but in the real world it is more like 5 times (or even more) that amount, according to tests I have seen. Also, measurement errors occur more frequently than you might expect.
Second is I don't know what you mean by imperfections in the print. If you ask the printer to print the same thing twice in a row, I would say it is extremely consistent. Visually and measurably, even when studying the dither pattern under high magnification. I have done this test many times before.
Again I strongly suspect that the interpolation and prediction of what colors a simulated i1 Pro might derive from simulated print converted through a printer profile is less than ideal. Mostly because the simulated i1 Pro "sees" color differently from yours. Device lamp spectrum differences, calibration, variances in the sensor, aperture grating etc.
It doesn't do a round-trip conversion, but it simulates the scan ...
Your diagram shows exactly the round trip conversion I am talking about RGB to lab to RGB. The final RGB should theoretically be the same source data used to make 1. the printed target and 2. the data for measurement simulation. The unknown to me is what happens to the RGB data after profile conversion to the simulated Lab values in fakeread? Although ArgyllCMS is open source, I'm not knowledgeable to understand the code yet.
It would be interesting to know what level of consistency you can achieve with your i1 Pro 2 for handheld measurements on a day to day basis. Your first test was excellent, more excellent than anything I have or seen others been able to achieve in scan mode, for large patch targets. Even tech support of X-rite Switzerland was unable to better my average best results, even when I had the target wrongly set up (nothing to do with wrong patch size input).
So (again, if I understand the test correctly) it's not a magic bullet or a cure-all, but it's a useful test and it's also very easy to run because all that's required is to print the target and scan it and the commands do the rest.
If you like doing it this way, by all means. No one can tell you what to do! :) But please do not come to the wrong conclusions, like saying common calibration is ok because you had low dE variances.
I do not think it is a useful test for me personally because it cannot help me isolate a problem if there is one. The amount of effort and time to make a print of a target and measure it is the same to start with, so I would much prefer to compare it to an actual measurement I made previously, than some simulated one. I am able to derive far more useful information out of this kind of test, and saves me time.
It isn't clear to me if the comparison is between the target printed using the print profile, against the Lab values of the reference, or whether the print profile is used so that the comparison is like the test I have here (that is, both fed through the profile). Do you know?
It compares against the Lab reference values of the target. That way you can tell if the profile is doing a good job of gamut mapping colors sampled from all over the RGB space, and where it might need to do a better job.
Yes, this sort of testing can be done in many different ways. I posted the link because it was well laid out online - a good spring board for coming out with more ideas too. It is interesting to study how these companies design their tests. Google translate helped me through all the German.
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Two problems here. One is that the spectrophotometer is not "accurate". In your one off test, it appears to be very consistent. A device can be consistently inaccurate if you know what I mean, like a ruler with an inaccurate scale. The i1 Pro varies from device to device by 0.4dE2k on average according to X-rite, but in the real world it is more like 5 times (or even more) that amount, according to tests I have seen. Also, measurement errors occur more frequently than you might expect.
Yes, you're entirely right, I was using sloppy language. I should have said consistent and not accurate. But it comes to the same thing in this test because the paper is profiled using the same i1Pro2 that is then used to scan the test target.
Second is I don't know what you mean by imperfections in the print. If you ask the printer to print the same thing twice in a row, I would say it is extremely consistent. Visually and measurably, even when studying the dither pattern under high magnification. I have done this test many times before.
Again, sloppy language on my part. What I mean is that the whole process of making the profile and then using it (via Photoshop, the CMM, the Print Plug-in) to print a target that is then scanned has inevitable inaccuracies due to the printer, the spectro, the software (for example, to print a spot color on the test target the likelihood is that the data will need to be interpolated and the new color may not print exactly as predicted), the physical media (ink, paper), even perhaps things like the room temperature and humidity, etc.
So again, if you print a target 5 times one after the other and measure the spot colors you may find that there is little variation between the prints ... so there is good repeatability, but not necessarily good accuracy.
What I am trying to measure is exactly that: the accuracy of the print, post rendering.
[As a second function, the test can be used to see if there is a drift over time (so, for example, the measurements may show an average dE of 0.5 today, but if I print the same target in a month's time I may get an average dE of 1.4, which would show that the printer calibration has drifted for this particular paper/ink combination)].
Again I strongly suspect that the interpolation and prediction of what colors a simulated i1 Pro might derive from simulated print converted through a printer profile is less than ideal. Mostly because the simulated i1 Pro "sees" color differently from yours. Device lamp spectrum differences, calibration, variances in the sensor, aperture grating etc.
Your diagram shows exactly the round trip conversion I am talking about RGB to lab to RGB. The final RGB should theoretically be the same source data used to make 1. the printed target and 2. the data for measurement simulation. The unknown to me is what happens to the RGB data after profile conversion to the simulated Lab values in fakeread? Although ArgyllCMS is open source, I'm not knowledgeable to understand the code yet.
What I mean by a round-trip would be to go through the profile in the forward and then the reverse direction. In this case the profile is only used once in the forward direction for both the print and the simulation. So we have an RGB image in the workspace that is converted to RGB colors for the printer (by the CMM/profile); and we have the exact same RGB image that is converted to RGB by fakeread through the same profile, and then converted to D50 Lab so that the spectrometer readings can be compared directly by colprof (it could be that fakeread doesn't convert to RGB at all but goes straight from the image RGB to Lab, but if it does convert to RGB then I don't know how it does the conversion to Lab ... I'll try to find out. Looking at the code it seems to be doing a conversion to RGB then back to Lab using a conversion matrix and white point adjustment, but the code is complicated and I don't understand what it's doing).
Of course the simulation is unlikely to be perfect: for example, the print used the Microsoft CMM whereas fakeread will use it's own internal conversion algorithms and there are bound to be differences there; and there could be programming errors in the Argyll code.
Like you I don't know enough about the internals to be able to gauge the simulation errors; but I would be pretty confident in the Argyll code as it's been out there for a long time and it's very widely used. Also, whatever error is introduced by the simulation should be consistent: so say the maximum simulation error is a dE of 1.0 ... well then you can take the test results as being correct to +/- dE of 1.0, which is still very good.
I think that perhaps the most useful thing is not the absolute accuracy of the test, but that it can highlight problem areas. For example if you find that all results have a dE of 1.0 or better, but 10 results have a dE of greater than 5 or 10 (or maybe much bigger) then the chances are that there is something seriously wrong with your profile or your printer (like nozzle clog, say). So you can then do some tests to see what the problem is.
It would be interesting to know what level of consistency you can achieve with your i1 Pro 2 for handheld measurements on a day to day basis. Your first test was excellent, more excellent than anything I have or seen others been able to achieve in scan mode, for large patch targets. Even tech support of X-rite Switzerland was unable to better my average best results, even when I had the target wrongly set up (nothing to do with wrong patch size input).
I'll try again in a week or so and let you know. It is a new instrument and perhaps I have a good one by luck. Also I am very careful in making sure the prints are well and truly dry and I scan very carefully ... slow and steady. Argyll uses lines between the spot colors and these may also help.
If you like doing it this way, by all means. No one can tell you what to do! :) But please do not come to the wrong conclusions, like saying common calibration is ok because you had low dE variances.
I do not think it is a useful test for me personally because it cannot help me isolate a problem if there is one. The amount of effort and time to make a print of a target and measure it is the same to start with, so I would much prefer to compare it to an actual measurement I made previously, than some simulated one. I am able to derive far more useful information out of this kind of test, and saves me time.
It compares against the Lab reference values of the target. That way you can tell if the profile is doing a good job of gamut mapping colors sampled from all over the RGB space, and where it might need to do a better job.
I'm not hung up on this test at all. What I'm trying to do at the moment is find a way of verifying my print system to try to make sure that it is as solid as I can make it. When I say that common calibration is OK, what I mean is that using common calibration followed by profiling (which takes out the calibration errors) appears to be producing good results on my printer. The test is one measure, but of course I'm also looking at prints visually.
Here is another test that compares two prints of a target:
===================================================================
rem Profcompare.bat iccprofile
targen -v -d2 -G -f100 ProfCompare1
copy ProfCompare1.ti1 ProfCompare2.ti1
printtarg -v -r -ii1 -a1.0 -T300 -M6 -pA4 ProfCompare1
printtarg -v -r -ii1 -a1.0 -T300 -M6 -pA4 ProfCompare2
cctiff -v -ir -e %1 ProfCompare1.tif ProfCompare1O.tif
move /Y ProfCompare1O.tif ProfCompare1.tif
cctiff -v -ir -e %1 ProfCompare2.tif ProfCompare2O.tif
move /Y ProfCompare2O.tif ProfCompare2.tif
Pause Print ProfCompare1.tif and ProfCompare2.tif with no color management
Pause Scan ProfCompare1
chartread ProfCompare1
Pause Scan ProfCompare2
chartread ProfCompare2
Pause The test results will be in ProfCompare.txt
colverify -v2 -N -k -s -w -x ProfCompare1.ti3 ProfCompare2.ti3 > ProfCompare.txt
==================================================================
This test can do two things: show the repeatability of your instrument (you can scan the same print twice and colverify will then give you the scan differences); show the drift over time of the printer calibration or print issues like head clogs (of course you would need to run the test in two goes, saving the first set of results so you can compare them to the second test).
I'm looking into a test to compare the image Lab values to the scanned Lab values, but although I think this would be useful, it would need to be used with care because the profile/CMM will change the data (that is it's job, after all). It would certainly show the extent to which the profile had shifted the values ... and if you saw some very large differences, particularly if they were clustered around a hue or saturation or lightness range then it might indicate a profile problem (but this would probably best be found visually using GamutVision or ColorThink).
Yes, this sort of testing can be done in many different ways. I posted the link because it was well laid out online - a good spring board for coming out with more ideas too. It is interesting to study how these companies design their tests. Google translate helped me through all the German.
Same here with Google translate :). I don't really understand what values ColorCheck are comparing and how they are doing it, but I assume that they are comparing the Lab values, and that they have chosen the target colors to be most likely within the printer gamut (they mention Fine Art and the target is an sRGB image). Of course this won't tell you what's happening for out-of-gamut colors, but I think some of their reports are quite interesting, for example the a* and b* plots.
I won't bother starting a new topic as it's more likely to end up in lots of arguments ... I just thought it might be useful to get some other people's input.
Robert
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Hi Robert, sorry for the delayed reply, I was busy.
It is good that we are on the same page regarding consistency.
What I am trying to measure is exactly that: the accuracy of the print, post rendering.
This is of course impossible, because you are using an inherently flawed device, not a reference grade spectrophotometer, to make the measurements.
Now that I think about it, fakeread most likely is just using the profile to convert from device RGB (your target patches) to Lab. While printing the target means using spectral data from measuring with your i1 Pro 2 to generate the Lab values. Therefore, Fakeread is not based on any reference or perfect i1 Pro. So I think we are sort of in agreement here on this one.
I am also now in agreement with you that the greatest contributor to the dE differences is interpolation error in the various conversion and measurement steps.
Also the accumulation of error, from your first round of measurements to build the profile, and the measurement of a print made with the profile, cannot be a good thing.
I am even more convinced that this is not a useful test. If you get low dEs everything is fine and dandy but I know nothing else. If it fails, I would have no idea what is contributing to this failure. I might as well conduct a more useful test to allow me to immediately separate printer and measurement issues from the onset. You may perhaps have a measurement error when creating the profile in the first place. It would still involve printing and measurement, but what you compare the measurement to is different.
There are better ways to verify if your profile is performing well or not. If you want to evaluate profile accuracy in terms of if I send L*50, will my printer print L*50? - this test does not answer that. If you want to know if your profile will render gradients smoothly, is free of banding, free of hue shifts etc, it does not answer it. If you wanted to know if calibration was helping put the printer in a more linear state, you need to graph the native performance of the printer before and after calibration. If you wanted to know if calibration on OEM Canon paper is better than third party papers, or if calibration on glossy is better than matte, you also need to graph the native performance of the printer.
then the chances are that there is something seriously wrong with your profile or your printer (like nozzle clog, say)
Quite honestly, if you had anything that seriously wrong with you printer, you will see it with your naked eyes just studying the print. No need for this time laborious test.
And if you have anything as subtly wrong with the dot pattern of the printer as I had been having, this test is not accurate enough to pick it up. You still need to look closely at the actual print outs.
I'll try again in a week or so and let you know. It is a new instrument and perhaps I have a good one by luck. Also I am very careful in making sure the prints are well and truly dry and I scan very carefully ... slow and steady. Argyll uses lines between the spot colors and these may also help.
Great. 2000+ patches is where it starts to get challenging, to measurement consistently without errors. I once measured over 100,000 patches in one sitting - not a good idea! Even the much more expensive iSis produces more measurement errors than I would like it to. Indeed, the separation lines between patches does help in software detection of the patches. Any i1 Pro 2 that passes the i1Diagnostics (http://www.xrite.com/i1diagnostics/support) test should be in good condition for measurement.
What I'm trying to do at the moment is find a way of verifying my print system to try to make sure that it is as solid as I can make it.
I'm afraid there is no one way of verifying this. You would have to use a variety of tests and experiments to discover this. And then at some point you will realise that making it solid (to borrow your word) for a particular paper will not work for another paper. Even on the same paper optimizing for dmax or gamut will cause you to sacrifice something else. Getting super accurate skin tones or spot colors may cause inevitable banding in other color gradients. It is all about constantly re-balancing depending on what kind of imagery you are printing.
Here is another test that compares two prints of a target.
Would it not be easier to just use the QA Analysis module in i1Profiler for this?
I don't really understand what values ColorCheck are comparing and how they are doing it, but I assume that they are comparing the Lab values
Yes, I think this is what is happening. Having a sampling of colors which will fall outside the gamut boundaries of the printer is not a problem - it is also useful to see how such colors are treated, especially when evaluating the perceptual rendering. Unless you going to do reproductions, I would be less hung up about the accuracy of image Lab compared to print Lab. Visual assessments are an excellent start.
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"What I am trying to measure is exactly that: the accuracy of the print, post rendering."
This is of course impossible, because you are using an inherently flawed device, not a reference grade spectrophotometer, to make the measurements.
Yes, of course any test that requires an instrument will never be 100% accurate. But you can say that if you use the same i1Pro2 for profiling and verification, that you do it in the same conditions as much as possible, that you allow the same amount of time for the ink to dry etc., that you can be confident that your comparisons are within a dE00 of x, relative to each other. We should be able to establish what x is with a reasonable level of certainty by doing several scans of a target and comparing the values.
I know, for example, that if I repeatedly measure the same spot color, that I start off with a dE94 of about 0.005 and that this drifts up to about 0.03 as the lamp heats up. If I move the device to a different spot on the color patch, the dE94 value can go up to about 0.3 max. I also know that if I recalibrate the device that the measurement changes by a dE94 of about 0.1. So the worst case is a dE94 difference of 0.4 between measurements (not taking into account any other error sources, like rounding or interpolation errors).
So straight away I know that the repeatability of the instrument is very good although it does drift a bit as the lamp heats up, that recalibration introduces a difference of about 0.1 and that with the particular paper (Canson Baryta in this case) there can be a variability of up to 0.3 over a 3cm square patch. So I can say that if I do a validation that the readings are only good to a dE94 of 0.4 (ignoring any other sources of error). That's well within the just noticeable difference range, so if I can get to this level of accuracy in a test it's better than I can see by visual inspection.
Now that I think about it, fakeread most likely is just using the profile to convert from device RGB (your target patches) to Lab. While printing the target means using spectral data from measuring with your i1 Pro 2 to generate the Lab values. Therefore, Fakeread is not based on any reference or perfect i1 Pro. So I think we are sort of in agreement here on this one.
Yes, I'm trying to pin down exactly what the various commands do, but at this stage I would be reasonably confident in saying that fakeread uses the AtoB1 (for relative) or AtoB3 (for absolute) profile table to convert the RGB test values to Lab. So the Lab value it produces is only as good as the forward tables. For this reason, it's important in a test either a) to eliminate any destination out-of-gamut colors, or to make sure that the colors are all in gamut (the easiest way to do that is to produce the RGB test values and then to Assign the destination profile to the image ... which is effectively what both cctiff and fakeread do, if I understand them correctly).
I am also now in agreement with you that the greatest contributor to the dE differences is interpolation error in the various conversion and measurement steps.
Yes, that's possibly true, especially if the profile was made from few color patches. To see how large this error might be, what I did was to generate an RGB target and run it through fakeread to get the in-gamut Lab values. I then converted one of the values back to RGB and then back again to Lab (using xicclu) and compared the two Lab values. I got a dE94 error of about 0.2. The profile I used was a pretty good one made from 2600 patches. So, based on this single test value, we could now say that our validation is only good to a dE94 of 0.6.
My own feeling is that we should not be concerned about validation errors of dE00 less 1.0. If the dE00 is over 1.0 then this could well be pointing to a problem somewhere, most likely not due to the instrument or to rounding/interpolation errors. As a dE00 of 1.0 is just noticeable, I think that's OK (after all, we're not looking for errors that we can't notice :)).
Also the accumulation of error, from your first round of measurements to build the profile, and the measurement of a print made with the profile, cannot be a good thing.
Yes, that's true: errors in the profile will certainly cause problems ... not just in a validation test but in the printed image. So trying to find out if the profile is OK (whether by using a 3D gamut map, doing a visual examination of a test print, or using some sort of validation test like the ones I'm looking at) is surely a useful thing to do.
I am even more convinced that this is not a useful test. If you get low dEs everything is fine and dandy but I know nothing else. If it fails, I would have no idea what is contributing to this failure. I might as well conduct a more useful test to allow me to immediately separate printer and measurement issues from the onset. You may perhaps have a measurement error when creating the profile in the first place. It would still involve printing and measurement, but what you compare the measurement to is different.
There are better ways to verify if your profile is performing well or not. If you want to evaluate profile accuracy in terms of if I send L*50, will my printer print L*50? - this test does not answer that. If you want to know if your profile will render gradients smoothly, is free of banding, free of hue shifts etc, it does not answer it. If you wanted to know if calibration was helping put the printer in a more linear state, you need to graph the native performance of the printer before and after calibration. If you wanted to know if calibration on OEM Canon paper is better than third party papers, or if calibration on glossy is better than matte, you also need to graph the native performance of the printer.
Sure, of course. I'm not suggesting that this a fix-all test. It's just a test which may or may not be useful. Personally, the very first thing I do after making a profile is to look at a 3D gamut map to see that the gamut looks OK, doesn't have any holes in it, has the expected gamut volume, appears smooth; then I look at the black and white density response to see how smooth it is and that I am getting the expected DMax. Then I check to see how it performs through a granger rainbow (visually on the monitor). Then I compare the profile to a similar profile (say one I've done before, or the manufacturer-supplied profile, to see the differences). After that I will do a test print and examine it visually to check things like gradient smoothness etc. THEN I may run the kind of test I'm talking about.
I guess that one very useful outcome of this discussion would be to come up with a procedure to check the print system, whether this is by doing test prints or by using validation tests, or by using inspection software like ColorThink and GamutVision, or by a combination of these.
Just out of interest, have a look at the Canson iPF6400 Baryta profile, perceptual intent: serious garbage!
"What I'm trying to do at the moment is find a way of verifying my print system to try to make sure that it is as solid as I can make it".
I'm afraid there is no one way of verifying this. You would have to use a variety of tests and experiments to discover this. And then at some point you will realise that making it solid (to borrow your word) for a particular paper will not work for another paper. Even on the same paper optimizing for dmax or gamut will cause you to sacrifice something else. Getting super accurate skin tones or spot colors may cause inevitable banding in other color gradients. It is all about constantly re-balancing depending on what kind of imagery you are printing.
Exactly. One test may reveal one problem whereas another may reveal another. For example, if you print with the Canson iPF6400 Baryta profile with Perceptual intent, you will most likely get a pretty bad result (but you might not, depending on the image). If you look at the profile using a 3D gamut viewer ... you will certainly see that it is totally flawed.
And, for sure, everything could be fine for one paper and completely bad for another (but in that case it would be reasonable to suspect the profile).
I do agree that the acid test is the print. But you certainly learn a hell of a lot when you start to look at various tests: not just from the point of view of whether things are right or not, but much more basic things like what happens to an image as it is being translated from input to working space to output, for example. A few years ago I would happily jump from ProPhoto to Lab to sRGB to print ... and things would be sort of OK; but now when I look at an image I'm immediately drawn to potential problem areas, like banding due to out-of-gamut clipping, for example. I think I understand what is going on much better than I used to, and I'm less likely to make silly mistakes that result in an inferior print (or web image).
"Here is another test that compares two prints of a target".
Would it not be easier to just use the QA Analysis module in i1Profiler for this?
No, once you have the batch files Argyll is very easy to use. It is also very flexible in what you can do. But then again, I haven't really looked at i1Profiler for quality assurance (I guess you need to either select or make a .pxf CGATs file, print and scan it twice and then use the Data Analysis to compare the results?).
Robert