Luminous Landscape Forum
Raw & Post Processing, Printing => Printing: Printers, Papers and Inks => Topic started by: Nickilford on April 09, 2018, 05:26:24 pm
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Hello everyone, first post here,
I run a fine art printing business in Lisbon, Portugal, use a Canon Pro4000 (previously had iPF8100) and so far am really satisfied with it.
I use Canson papers that i love but noticed a slight shift in colour when matching print to screen with a new paper I purchased, Canson Baryta Prestige. I use i1 Photo Pro 2 to profile all my papers and monitor and have perfect results with every other paper i use, but the Prestige seems magenta-ish in the midtones especially. I tested the exact same (colour) image on Canson Platine and it looked fine, same as on my monitor. Then i tried the Platine profile with the Prestige and it improved slightly. When looking at the print isolated, it looks fine but when comparing to monitor or to the print made on Platine it looks different... more magenta. The difference in paper white between Platine (more natural, creamy white) and Prestige (colder white) is noticeable.
Has anyone had this experience with Prestige or any other paper? Could it be a problem with the profile i made? Any suggestions on how to get to the bottom of this?
Thanks!
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I reviewed this paper on this website, custom profiled it and noticed no such problem. I suspect of you remade the profile you would get better results. If you are using i1Profiler, try making your profile with the 2371 scrambled patch layout, test it and see what happens. Generate the patch set in i1Profiler (4 letter size pages), save them out as TIFFs to your hard drive and use Canon's Print Studio Pro for printing these targets with No Color Controls selected in the Color Management section of Print Studio Pro (lower right of the interface if I remember correctly.
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I reviewed this paper on this website, custom profiled it and noticed no such problem. I suspect of you remade the profile you would get better results. If you are using i1Profiler, try making your profile with the 2371 scrambled patch layout, test it and see what happens. Generate the patch set in i1Profiler (4 letter size pages), save them out as TIFFs to your hard drive and use Canon's Print Studio Pro for printing these targets with No Color Controls selected in the Color Management section of Print Studio Pro (lower right of the interface if I remember correctly.
Seems like extra steps. Isn't one able to do the same printing in I1Profiler or are the settings obscure? That's worked for me on my Canon and Epson and it makes very good profile targets for both the I1Pro 2 and iSis. The large patch set will produce a very good profile but there shouldn't be a magenta cast with the 2 page (I1Pro) 918 patch set. If the process fails with that, a larger one has a high probability of failing too as it indicates some procedural error. Perhaps the Print Studio Pro eliminates incorrectly setting color management off? I would still be inclined to make the smaller profile first to make sure that approach is working.
Also, measuring a part of the print showing the magenta tint, then printing a patch of it with Abs. Col. then measuring that patch would let one see any color shift that's occurring.
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I reviewed this paper on this website, custom profiled it and noticed no such problem. I suspect of you remade the profile you would get better results. If you are using i1Profiler, try making your profile with the 2371 scrambled patch layout, test it and see what happens. Generate the patch set in i1Profiler (4 letter size pages), save them out as TIFFs to your hard drive and use Canon's Print Studio Pro for printing these targets with No Color Controls selected in the Color Management section of Print Studio Pro (lower right of the interface if I remember correctly.
I usually make all my profiles using 2033 scrambled patches and have thought of re-profiling. I have never encountered this problem and all my papers match screen. Would the extra 300-so patches make a difference regarding cast? I have a strong feeling it won't but i suppose it's worth a try.
Thanks
I also thought of creating different monitor profiles for different papers where warranted for. Most, if not all, papers work great with a monitor white point of 6000k... would adjusting WP for this paper help? If so how do i measure paper WP properly with i1 Photo Pro 2... with the device in contact with paper or at a distance?
Thanks
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I've had no problem with Prestige at all, in fact it's become my favorite paper. I just use Canson's canned profile and the results are great, but I'm using a Epson.
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Check Ethan Hansen's major post in this Forum (some time back) on preferred patch set sizes for i1Profiler. 2371 is a recommended one, 2033 isn't. 1877 is another preferred combination which I've also tested and found 2371 to be marginally more accurate. It isn't so much the number of patches that matters, it's the composition. As for using Print Studio Pro - it can be preferable to i1Profiler for printing targets for this new Canon Pro series of printers. This is according to Canon technical support in New York, I've tested it, and I know it's good. The issue is indeed assuring that Color Management is really OFF as understood by this printer driver.
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I've had no problem with Prestige at all, in fact it's become my favorite paper. I just use Canson's canned profile and the results are great, but I'm using a Epson.
Since I have been able to make my own profiles i just never remember this! Great way to test my profile!Thanks great idea!
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Check Ethan Hansen's major post in this Forum (some time back) on preferred patch set sizes for i1Profiler. 2371 is a recommended one, 2033 isn't. 1877 is another preferred combination which I've also tested and found 2371 to be marginally more accurate. It isn't so much the number of patches that matters, it's the composition. As for using Print Studio Pro - it can be preferable to i1Profiler for printing targets for this new Canon Pro series of printers. This is according to Canon technical support in New York, I've tested it, and I know it's good. The issue is indeed assuring that Color Management is really OFF as understood by this printer driver.
Thanks Mark, i didn't know this... from now on i will do the 2371. I will try and track Ethan's post down. CHeers
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It's not the number of patches per se, it's the patches used. I've yet to find more patches really beat Bill Atkinson's designed patch set; 1728 does the job quite well. And then, if so desired, a post optimization using i1P which can make very subtle improvements or none at all.
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It's not the number of patches per se, it's the patches used. I've yet to find more patches really beat Bill Atkinson's designed patch set; 1728 does the job quite well. And then, if so desired, a post optimization using i1P which can make very subtle improvements or none at all.
Raises a question in my mind about what's changed since this discussion of some years ago: Profiling (http://forum.luminous-landscape.com/index.php?topic=54384.0)
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Raises a question in my mind about what's changed since this discussion of some years ago: Profiling (http://forum.luminous-landscape.com/index.php?topic=54384.0)
I finally got my 9800 singing. It had the largest variation dE2k in the neutrals and near neutrals. I wound up making 4 sets of patches and that has yielded the best overall profile accuracy and went a long way to cleaning up the neutrals.
The 4 patch sets are each 957 count so they fit on a letter size iSis target. The consist of :
1. The original (default) iSis 957 patch target.
2. Two pages of patches (1914 count) generated from the I1P optimizer.
3. One page of patches along the neutral axis with a grid size of 37 and including all near neutrals. This was chosen to coincide exactly with the grid spacing of the high quality I1P profile setting.
These were rounded to 8 bits and combined into a single CGATs file 3828 in size or 4 iSis pages.
Here's a plot of printed then measured Lab values over a range of L=0 to L=100. Note the limits at L*=5 and 95 which are the paper's black and white points respectively.
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Singing indeed! That is an excellent outcome. Congrats. Have you tested it for colours yet?
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Singing indeed! That is an excellent outcome. Congrats. Have you tested it for colours yet?
It's been something of a struggle to get the neutrals tracking on my Epson 9800. Much less so than the Canon because of the way they mix CYM with the neutral inks. One can see this by measuring how the patch colors change when printing a target with just RGB values going from (0,0,0) to (255,255,255) w/o color management.
Much of the problem is from using DeltaE2000 v DeltaE1976. dE2k is far more sensitive to small hue and chromaticity changes near the neutrals and much less sensitive to changes in even moderately saturated colors. dE2k is a better metric to optimize because it more closely matches human vision sensitivity.
I did get better results by using the I1P target sets that Ethan's excellent post suggested, but the neutrals and near neutrals were still far enough apart that it only reduced some of the 9800's neutral variation.
So first I focused on using I1P's "optimize" process starting with the 957 default patch set to create an additional 1914 "optimized" patches. This did an excellent job improving accuracy of colored patches but had little effect on the near neutrals. After thinking about it a bit I made a set of neutral and near neutral patches that covered the entire space along the same grid spacing as the AtoB1 tables. This had patches at every position on the "neutrals" and near "neutrals" which are adjacent in the A2B1 tables. From this set I made a 957 patch, single iSis page, of these target RGB sets.
Then I just added this page to the original, iSis 1 page default set, and the color "Optimized" 2 page set to make a 3828 patch, 4 page profile target.
This resulted in a 4 page set of patches that produced not only excellent tracking in the neutrals, a real problem on the 9800, but also very good color accuracy of other, in gamut, colors.
Turns out the patch set is excellent for all glossy and semigloss type papers on the 9800.
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Much of the problem is from using DeltaE2000 v DeltaE1976. dE2k is far more sensitive to small hue and chromaticity changes near the neutrals and much less sensitive to changes in even moderately saturated colors. dE2k is a better metric to optimize because it more closely matches human vision sensitivity.
Really? In my experiments comparing dE1976 to dE2000, they both returned nearly identical response in neutrals/near neutrals. No real reason to move to dE2000 if one is concerned with neutral and low chroma color accuracy. dE2K does lower the magnitude of the response in higher chroma colors, particularly in certain hues, but measurement of greyscale neutrality should not be any better or worse using de1976 versus de2K. That said, the perceptual "fudge factors" built into the dE2000 math were still designed to improve the scaling of human observed "perceptual magnitude" differences when comparing more vivid colors aligned 2-up side by side on a simple grey surround at a specific angular magnification (2 degree or 10 degree). De2K is therefore superior for simple color matching work like comparing paint or textile matches, but still not right for evaluating the color accuracy which is observed in complex color scenes like what we routinely see in prints, paintings, and photographs.
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I finally got my 9800 singing.
Super.
How well do believe that particular profile would behave if you were to share it among the general population using the same printer / ink / media / settings combination?
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Raises a question in my mind about what's changed since this discussion of some years ago: Profiling (http://forum.luminous-landscape.com/index.php?topic=54384.0)
Bills iteration and X-rite's are not the same for one.
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Really? In my experiments comparing dE1976 to dE2000, they both returned nearly identical response in neutrals/near neutrals. No real reason to move to dE2000 if one is concerned with neutral and low chroma color accuracy. dE2K does lower the magnitude of the response in higher chroma colors, particularly in certain hues, but measurement of greyscale neutrality should not be any better or worse using de1976 versus de2K. That said, the perceptual "fudge factors" built into the dE2000 math were still designed to improve the scaling of human observed "perceptual magnitude" differences when comparing more vivid colors aligned 2-up side by side on a simple grey surround at a specific angular magnification (2 degree or 10 degree). De2K is therefore superior for simple color matching work like comparing paint or textile matches, but still not right for evaluating the color accuracy which is observed in complex color scenes like what we routinely see in prints, paintings, and photographs.
dE2k is less affected at lower saturation levels than dE76 but can still be over 40% more sensitive. Especially to hue angle changes but is also more sensitive to saturation increases than dE76.
At higher saturations dE2k is certainly much less sensitive. There is about a 2x to 4x difference as saturation increases: See:
http://forum.luminous-landscape.com/index.php?topic=111560.msg921607#msg921607
As for how well any of these work in complex scenes as opposed to comparing two patches in a neutral surround, at best this is a multidimensional problem but the general consensus seems to be that as scenes become more complex color differences become less noticeable. Probably the most critical area for a dE metric is determining the threshold of visible banding around any color. I find dE2k, while certainly flawed, is better at it than dE76.
Black and white printing is less complex in many ways. And I've found dE2k to be considerably better than dE76 when characterizing how neutral black and white printed images appear. I can sometimes notice a dE2k shift of 1.5 in neutrals where it might only be a 1.0 dE76. And it is quite consistent with what dE2k is telling me about those differences.
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Super.
How well do believe that particular profile would behave if you were to share it among the general population using the same printer / ink / media / settings combination?
While I think it would be good, it's tailored to the 9800 and that prints darker targets than most current printers. The additional 'optimized" I1P patches are much lighter. Presumably to better cover the printable gamut.
I'm working on a generic target that is heavily optimized for the I1Profiler's LUT structure. It has full coverage for the neutrals and near neutrals as well as RGB values that align with the I1Profiler's A2B1 LUT structures when selecting highest quality.
It should be quite good for general profiling and especially profiles that are used for B&W or images that have a great deal of neutral and near neutral colors where vision is more sensitive to small changes.
I will post a CGATs file for importing into I1Profiler to create I1Pro targets as well as tiff files for printing iSis targets. This will be in a new thread shortly.
Update: I put CGATs, tiff files, and I1P chart format files (.txf) in a zip file at the end of a (too long) background post outlining the evolution of this, now generic, profile target on the Color Management Forum.
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... use Canon's Print Studio Pro for printing these targets with No Color Controls selected in the Color Management section of Print Studio Pro...
Just about to redo the print target and since I usually use Adobe Color Printer Utility for printing targets I was wondering if using Canon's Print Studio Pro would make any difference for this purpose?
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The reason why I recommended this is because I and others have come across issues using ACPU for printing profiling targets with this printer driver. It comes from a recommendation that Canon technical support made to me when I was testing the Canon Pro-2000 printer, and I found that their advice produced a reliable path through "no colour management" which is necessary for successful profiling. Nothing prevents you of course from trying either, or from using i1Profiler for that matter, and observing any differences in outcomes. Could be interesting - just more ink, paper and time.
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The reason why I recommended this is because I and others have come across issues using ACPU for printing profiling targets with this printer driver. It comes from a recommendation that Canon technical support made to me when I was testing the Canon Pro-2000 printer, and I found that their advice produced a reliable path through "no colour management" which is necessary for successful profiling. Nothing prevents you of course from trying either, or from using i1Profiler for that matter, and observing any differences in outcomes. Could be interesting - just more ink, paper and time.
Thanks Mark, this is valuable info. Actually I just printed a target for Canson Aquarelle Rag via Canon's Print Studio Pro, the target for Prestige had already been printed yesterday through ACPU, sorry my mistake. I followed your instructions regarding the the patch count (2371) though, so i'm curious about the results. Will be reading the Prestige target shortly and will post outcome back here.
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I reviewed this paper on this website, custom profiled it and noticed no such problem. I suspect of you remade the profile you would get better results. If you are using i1Profiler, try making your profile with the 2371 scrambled patch layout, test it and see what happens.
So, I re-profiled the Prestige with the 2371 scrambled patch and the results are better but not that much better. I had already printed the target via ACPU before the OP, so now i have printed through the Canon Print studio pro and am going to give it another go.
Btw, does the lighting i am reading the target under have any influence on profile quality?
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So, I re-profiled the Prestige with the 2371 scrambled patch and the results are better but not that much better. I had already printed the target via ACPU before the OP, so now i have printed through the Canon Print studio pro and am going to give it another go.
Btw, does the lighting i am reading the target under have any influence on profile quality?
I haven't conducted any tests to know whether reading the targets under dim, bright or no light makes a difference, so I can't say. I normally read profiling targets under dim lighting, using an i1Pro 2 and the supplied baseboard and track. The i1Pro2 design looks as if it is protected from ambient light, but how much and how well I don't know.
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Btw, does the lighting i am reading the target under have any influence on profile quality?
Not really unless you had a massive amount pointed at the unit etc. It’s pretty well blocked. The color under the paper could if not totally opaque. Maybe a 2nd blank sheet under the print target in such cases could be prudent.
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I haven't conducted any tests to know whether reading the targets under dim, bright or no light makes a difference, so I can't say. I normally read profiling targets under dim lighting, using an i1Pro 2 and the supplied baseboard and track. The i1Pro2 design looks as if it is protected from ambient light, but how much and how well I don't know.
This is how I usually read targets and have had good results so far.
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It’s pretty well blocked.
My thoughts exactly! Just wanted to have more experienced people's thoughts on this. The papers I use are pretty heavy so i don't think opacity will be an issue.
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Don't you use the backer-board that comes with the i1Pro2 kit? It's been designed specifically for neutral influence.
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Don't you use the backer-board that comes with the i1Pro2 kit? It's been designed specifically for neutral influence.
Yes I use all original accessories that come with the i1PP2.
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Don't you use the backer-board that comes with the i1Pro2 kit? It's been designed specifically for neutral influence.
Yes (when I use that product) but it's still a good idea to place another sheet of paper there and in the past, there was controversy about using a black backer instead of white.
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Does the speed at which one reads each row have any influence on profile quality? I'm assuming that as long as you don't get an error all is good, but something keeps telling me that the slower you go the more time the sensor has to pick up info. What has been your experience?
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Yes, speed matters. Up to a point, slower is better. As you pass over each patch, the instrument is reading a certain number of samples per second (I forget the exact specification), so passing over the patches more slowly increases the number of samples read per patch, which means that average for the patch will be more representative and presumably a more accurate representation of the printed colour.
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OK got it - in scanning mode 200 samples per second. So if you scan a whole row in 20 seconds, you have collected a total of 4000 samples; assuming an even pass, if there are 30 patches in the row, you would be picking up 133 samples per patch, which would be averaged for each patch.
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OK got it - in scanning mode 200 samples per second. So if you scan a whole row in 20 seconds, you have collected a total of 4000 samples; assuming an even pass, if there are 30 patches in the row, you would be picking up 133 samples per patch, which would be averaged for each patch.
Wow, this takes target reading to whole new level... I thought I was going slow at 5secs per row!
Thanks for the numbers, really puts things into perspective.
Just finished ready the target for Prestige, printed from Print Studio Pro, linear patches 2371. Be right back.
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Did you let the target print dry for at least a few hours? There can be subtle colour shifts during the first few hours of dry-down. Some people give them overnight.
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Did you let the target print dry for at least a few hours? There can be subtle colour shifts during the first few hours of dry-down. Some people give them overnight.
Yes I usually give 24h, sometimes more.
Since i have had this printer i only use the ICC profile i created but in the MCT i have never used the Calibration target module. Will this help in any way even if i already use a custom profile?
P.S - just ran a test print and the result was worse than the profile i scanned yesterday. I may be being a bit too nitpicky here, taking a closer look I might be mistaking a higher saturation in certain areas than an actually color shift....
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You need a defined process to cross check profiles. This means a test of independent colors, not used in the creation of the profile, printed using normal, Photoshop manages color and selecting the intent and profile.
Then, measure the printed colors.
Easiest way by far is to grab a tiff image of a ColorChecker from BabelColor. Print it selecting Abs. Col. then measure the 24 patches using the "Measure" tab and select a 4x6 grid layout to match the Colorchecker. Use spot measure for the I1Pro or I1Pro2.
Now compare the Lab values by clicking on each patch. Compare to those examining the image in Photoshop. You should see an average dE of 1 or less except for the white patch which is often outside the printable gamut unless the paper white is above L*=96.
Pay special attention to the neutral patches on the bottom of the CC.
You can also save the measurements by selecting the save button. Select a CGATs format for simple reading with a text editor or Excel. Makes it easier to collate the data.
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Does the speed at which one reads each row have any influence on profile quality?
To a minor degree yes in that it scans 100 samples a second and averages them but if you go too fast, you'll get an error and that's a lot of sampling. Perhaps with canvas or some textured paper it might be somewhat prudent to move a bit more slowly but even 1 'good' measurement would likely be enough. At least in the old days, many Spectrophotometer's only needed one.
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No big deal, but according to the specs (i1Pro2) it's 200 per second, which is better of course.
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No big deal, but according to the specs (i1Pro2) it's 200 per second, which is better of course.
Yes, than i1Pro which is 100; which is the OP using?
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One difference the I1P and I1Pro 2 have over the older I1Pro is that chart scanning is done with quadrature position sensing on the underside of the Spectro. The earlier one looked for contrast differences between adjacent patches because it didn't have the quadrature position info. The contrast info that matters is the white/black bars at each row end. This establishes the patch locations using the quadrature info. If it's anything like the iSis, it heavily weights middle samples that are 2 mm from the actual patch edges. This is actually testable and I've done that for the iSis. Might be interesting to do for the I1Pro 2.
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Yes, than i1Pro which is 100; which is the OP using?
In the opening post OP says i1Pro2.
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One difference the I1P and I1Pro 2 have over the older I1Pro is that chart scanning is done with quadrature position sensing on the underside of the Spectro. The earlier one looked for contrast differences between adjacent patches because it didn't have the quadrature position info. The contrast info that matters is the white/black bars at each row end. This establishes the patch locations using the quadrature info. If it's anything like the iSis, it heavily weights middle samples that are 2 mm from the actual patch edges. This is actually testable and I've done that for the iSis. Might be interesting to do for the I1Pro 2.
If you checked it, would the answer inform the profiling process in any particular way? The only choices we have in regard to the scanning procedure are whether to scramble the patches and how slowly to scan them. Safest and most reliable option set is to scramble (even if not strictly necessary) and scan slower rather than faster. Typically with about 30 patches per row, if you think 100 samples + per patch is enough for good averaging (smothering outliers), spending about 20 seconds on a row would seem to do it appropriately. The larger the number of total samples per patch in theory the less important any weighting would be - do you think?
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If you checked it, would the answer inform the profiling process in any particular way? The only choices we have in regard to the scanning procedure are whether to scramble the patches and how slowly to scan them. Safest and most reliable option set is to scramble (even if not strictly necessary) and scan slower rather than faster. Typically with about 30 patches per row, if you think 100 samples + per patch is enough for good averaging (smothering outliers), spending about 20 seconds on a row would seem to do it appropriately. The larger the number of total samples per patch in theory the less important any weighting would be - do you think?
The main advantage to the quadrature positioning info is that you don't have to be as careful to smoothly move the spectro across the patches. You can even briefly stop mid row without a problem. A secondary advantage is that the patches don't have to provide patch to patch contrast changes which is required by the older I1Pro.
I generally did a fairly fast row scan with the I1Pro 2 of around 4 seconds. 2 seconds was too short.
The iSis doesn't use quadrature but rather a stepper motor with better precision. It also does not use adjacent patch contrast at all so one can layout patches any way desired.
I almost always scramble patches. It doesn't seem to affect the 9800 one way or the other but it does produce slightly worse profiles on my 9500II.
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For positioning I can see that, but I was asking about the importance of knowing whether the spectro centre-weights the measurements - which I wonder whether an i1Pro 2 does. It knows where it is by virtue of the striped grid it is reading as it moves along and the patch it is reading in real time; its reading is timed as so many samples per second; to centre-weight the samples in time it would have to do complex calculations with instant feedback tracking the varying speed that the user deploys reading a row. Seems improbable. The iSis is a different animal - fixed and known speed so fewer variables in real time.
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For positioning I can see that, but I was asking about the importance of knowing whether the spectro centre-weights the measurements - which I wonder whether an i1Pro 2 does. It knows where it is by virtue of the striped grid it is reading as it moves along and the patch it is reading in real time; its reading is timed as so many samples per second; to centre-weight the samples in time it would have to do complex calculations with instant feedback tracking the varying speed that the user deploys reading a row. Seems improbable. The iSis is a different animal - fixed and known speed so fewer variables in real time.
Yes, the iSis does have those advantages. The I1Pro2 would have to window it's samples, excluding those where the 4mm aperture has potential for overlapping two patches plus accounting for error. A design approach would be quite straightforward. Include all samples in the window, add them, then divide by the number of samples in that window. It may, or may not, include some sort of window rolloff like the iSis which uses a Gaussian window giving the most weight to readings within 1mm of the patch center. I would think that part of the program code could be quite similar. The only reason I can think of for not using a rectangular window is that if registration errors occurred or the paper dried with a slightly uneven shrinkage then a Gaussian window would reduce those errors.
But there is a tradeoff. The Gaussian window images a narrower part of the patch and so paper irregularities are more likely to show up. It also increases the noise (less photons) but that effect is miniscule. The illuminant is so intense that the shot noise is vanishingly small when measuring reflectance spectra.
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Thanks to all who have helped with this topic, I have managed to come up with a satisfactory result with the Canson Prestige and have learned quite a bit in this thread alone. Some of the info left by more seasoned users is going to take me a while to digest but will get around to it with a little more time.
Once again thanks a lot!
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You are welcome. I'd be curious to know what you did, in the final analysis, to come up with a successful result. Would be interesting, given the variety of opinions and suggestions in this thread.
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You are welcome. I'd be curious to know what you did, in the final analysis, to come up with a successful result. Would be interesting, given the variety of opinions and suggestions in this thread.
For the most part I followed your advice Mark. I had a go trying the linear target route after I thought the scrambled target didn't improve all that much. But then ended up settling with the scrambled 2371 patch target. Also found better results with ACPU rather than PSP (Print Studio Pro) I would still say that I am not "as satisfied" with the Prestige profile as I am with all my other papers (Canson or not) but still feel pretty good with the prints. It seems I was thrown off a bit by the increased saturation with the prints on Prestige, probably mistaking the more intense colours with a colour shift instead. I'm really picky and can (un)fortunately pick up even the slightest colour shift.
Here was what I used:
— target printed from ACPU (Adobe Color Printer Utility), didn't like the results when printed from PSP
— 2371 scrambled patch layout
— target read speed about 5 sec/row (will decrease the speed in the future)
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Thanks for the info. Interesting that you derived better results from using ACPU rather than PSP on the Pro-4000. But it is what it is.......whatever works best.