Luminous Landscape Forum
Raw & Post Processing, Printing => Printing: Printers, Papers and Inks => Topic started by: NeilPrintArt on July 29, 2019, 12:27:45 pm
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Hello,
I am a bit baffled as to how to measure printed dmax on a paper.
I am trying to determine the best media type to use when profiling a particular cotton rag (Hahnemuhle PhotoRag in this case)
I have printed the same test image with a number of different media types (WRCW, Velvet Fine Art etc) and now I want to use my i1Pro2 to read the black patch on the test image to determine which media type gives me the best dmax.
But how is one supposed to read a single patch in either iProfiler or Colorport. I'm stumped! Have looked online and on this forum but can't find the answer.
Easy to ready an existing test chart, but for the life of me can't figure out how to read a single patch.
I can set iProfiler to read a single patch, and then see the L*a*b values, but how to translate that to dmax?
Thanks so much!!
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Been many years since I did this, at the time I used ProfileMaker's MeasureTool which reported density.
Today, you can use PatchTool from BableColor, the manual states:
By selecting this export option, you can convert a file spectral data into reflection density values as defined in ISO
SpectraShop can also provide this:
Visual Density (reflective and transmissive)
Used to evaluate the lightness or darkness of an image to be viewed directly (e.g. prints) or projected (e.g. black-and-white transparencies). It can be used to evaluate any material viewed by the human visual system, with or without color.ISO Type 1 Density (reflective)
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Hello,
...But how is one supposed to read a single patch in either iProfiler or Colorport. I'm stumped! Have looked online and on this forum but can't find the answer.
Easy to ready an existing test chart, but for the life of me can't figure out how to read a single patch.
I can set iProfiler to read a single patch, and then see the L*a*b values, but how to translate that to dmax?
Thanks so much!!
Just use the "measure chart" feature of i1Profiler, and set the rows per page and columns per page to 1, and you've got a single spot to measure. That said, I usually set columns per page to several or more so I can take several spot readings at a time and quickly compare them. Then just measure your chosen patch, select it, and i1Profiler gives you numerous options that will display on the left side of the window. One option is density (you can even choose status A, status T, etc). You will see the "visual density", plus cyan (red channel), magenta (green green channel), and Yellow (blue channel) density readings listed as well.
FWIW, although many photographers like to see maximum printable black patch values expressed as "Dmax", the L* value of the blackest printable patch, IMHO, is an even more useful expression of the perceived "blackness" of a the patch because L* is a more perceptually uniform scale.
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Just use the "measure chart" feature of i1Profiler, and set the rows per page and columns per page to 1, and you've got a single spot to measure. That said, I usually set columns per page to several or more so I can take several spot readings at a time and quickly compare them. Then just measure your chosen patch, select it, and i1Profiler gives you numerous options that will display on the left side of the window. One option is density (you can even choose status A, status T, etc). You will see the "visual density", plus cyan (red channel), magenta (green green channel), and Yellow (blue channel) density readings listed as well.
FWIW, although many photographers like to see maximum printable black patch values expressed as "Dmax", the L* value of the blackest printable patch, IMHO, is an even more useful expression of the perceived "blackness" of a the patch because L* is a more perceptually uniform scale.
I use Colorunki Photo in Spot Measure mode to get the L*ab values but apparently it does not have the capability for conversion to D. What's the best way to make a conversion then. I thought there was a web resource for this but I can't find it anymore.
:Niranjan
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There is a Spectral Calculator Spreadsheet on Bruce Lindbloom's website, feed it spectral data and it will provide density values.
Richard Southworth
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There is a Spectral Calculator Spreadsheet on Bruce Lindbloom's website, feed it spectral data and it will provide density values.
Richard Southworth
He has Lab values; he needs spectral data. If he can get such measurements, I’d be happy to plug that into one of the two products I mentioned.
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Thanks for the replies to my question as to how to measure the dmax of a printed 100% black patch. Turns out to be super easy in fact if you have a i1pro2. I had an idea in my head that it wasn't possible from i1profiler. But was just looking in the wrong place (thanks MHMG for pointing me right).
And also easy to do from Colorport -
Create single patch chart .. measure in spot mode .. click in 'i' in measurement status .. measurement info .. presto!
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What I am in the process of doing is trying to determine the optimal 'media type' settings to use when creating a new paper profile...
Environment is OSX/Epson/UC using Mirage as a printer driver. Paper is Hahnemuhle PhotoRag 308gsm
I created a medium size (1215 patches) test chart in iProfiler
I printed the test chart (untagged) using Mirage in 'Profile Creation' mode using different media types (Enhanced Matte, UltraSmooth, WCRW and Velvet Fine Art).
Left the printed charts overnight then scanned using my i1pro2 and created new profiles, one for each media type.
My understanding is that the media type controls the amount of ink put down as well as the halftone/dithering algorithm?
There does seem to be a difference in the profiles created. Attached below is a screengrab from Colorsync Utility in the Mac OS which allows you to visually look at profiles. This is in the Lab space. The placeholder profile (lighter) is the Enhanced Matte. The overlay profile (colourful) is the Velvet. It seems to me there is fair bit of space in the shadows, especially the blues, that I would gain from using the Enhanced Matte media type.
I am sure this is old news to a lot of people but certainly I am surprised.
The proof is in the pudding as they say and the next step is to print a range of real life images and compare
Would be curious as to other peoples preference as to media type as well,
thanks so much
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What I am in the process of doing is trying to determine the optimal 'media type' settings to use when creating a new paper profile...
That's not too difficult; output this file using a few such media settings, pick the one that visually has the best tonal separation.
http://digitaldog.net/files/InkDensity.zip (http://digitaldog.net/files/InkDensity.zip)
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That's not too difficult; output this file using a few such media settings, pick the one that visually has the best tonal separation.
http://digitaldog.net/files/InkDensity.zip (http://digitaldog.net/files/InkDensity.zip)
Thanks Andrew. Yes this is one of the test images I have been using. I reference your site and instructional videos all the time, much appreciated!
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I have used THIS (https://www.on-sight.com/how-to-determine-the-optimal-media-selection-for-any-paper/) as an aid in finding the optimal media selection for papers. Scott Martin gives a good explanation on how to use it.
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What I am in the process of doing is trying to determine the optimal 'media type' settings to use when creating a new paper profile...
Environment is OSX/Epson/UC using Mirage as a printer driver. Paper is Hahnemuhle PhotoRag 308gsm
I created a medium size (1215 patches) test chart in iProfiler
I printed the test chart (untagged) using Mirage in 'Profile Creation' mode using different media types (Enhanced Matte, UltraSmooth, WCRW and Velvet Fine Art).
Left the printed charts overnight then scanned using my i1pro2 and created new profiles, one for each media type.
My understanding is that the media type controls the amount of ink put down as well as the halftone/dithering algorithm?
There does seem to be a difference in the profiles created. Attached below is a screengrab from Colorsync Utility in the Mac OS which allows you to visually look at profiles. This is in the Lab space. The placeholder profile (lighter) is the Enhanced Matte. The overlay profile (colourful) is the Velvet. It seems to me there is fair bit of space in the shadows, especially the blues, that I would gain from using the Enhanced Matte media type.
I am sure this is old news to a lot of people but certainly I am surprised.
The proof is in the pudding as they say and the next step is to print a range of real life images and compare
Would be curious as to other peoples preference as to media type as well,
thanks so much
Interesting results. Thanks for sharing.
So which one did you find had the best black Dmax? Also, since Enhanced Matte setting seem to give best overall profile from your results, is that the same as what Hahnemuhle recommends or different?
Another question comes to my mind is what happens to the sharpness with different media settings. In my experiments with playing around with ink density to maximize digital negative opacity, I learned that sharpness suffered at higher ink loadings.
:Niranjan.
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I have used THIS (https://www.on-sight.com/how-to-determine-the-optimal-media-selection-for-any-paper/) as an aid in finding the optimal media selection for papers. Scott Martin gives a good explanation on how to use it.
Hi Alan, thanks for this, yes this is another great resource.
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Hi Nirajan, I am still in the process of testing and will post more results later,
I do have a question for the experienced users on the forum and that is whether it is necessary to create a separate profile for each print resolution and mode?
Do I need a separate profile for the same ink/paper/machine combination printing at 720x1440dpi in bidirectional mode as opposed to printing at 1440x2880dpi in unidirectional mode, for example?
thanks
Neil
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Hi Nirajan, I am still in the process of testing and will post more results later,
I do have a question for the experienced users on the forum and that is whether it is necessary to create a separate profile for each print resolution and mode?
Do I need a separate profile for the same ink/paper/machine combination printing at 720x1440dpi in bidirectional mode as opposed to printing at 1440x2880dpi in unidirectional mode, for example?
thanks
Neil
IMO, no you don't. Printing out color patches for profiling is not the same as printing out images where color changes and even gradients within the color are critical. The different setting you reference may impact fine details in a print but not in a color patch. I use Argyll for profiling and on my old Epson and now my Canon Pro-1000, I use bidirectional printing and specify native DPI for the patch charts (360 for Epson and 300 for Canon) in Argyll.
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Hi Nirajan, I am still in the process of testing and will post more results later,
I do have a question for the experienced users on the forum and that is whether it is necessary to create a separate profile for each print resolution and mode?
Do I need a separate profile for the same ink/paper/machine combination printing at 720x1440dpi in bidirectional mode as opposed to printing at 1440x2880dpi in unidirectional mode, for example?
No; one profile for all.
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Thanks Alan and Andrew!
One final question....I am using iProfiler to create my test charts, usually 2033 patches The charts are automatically created by iProfiler with at low PPI (around 100ppi i think). But when I send the test chart (untagged) to the print pipeline, I assume the printer (Epson) is up-sizing the file (to 360 ppi). My questions is whether there is anything to be gained by doing the up-sizing of the test chart myself in Photoshop? And if so which of the algorithms to use? I would guess Nearest Neighbor? While of course being careful not to let the test chart be managed or tagged at all while it is PS?
BTW it was Andrew's "Not All Profiles Are Created the Same" video that prompted me to try and create a better profile then the one I have been using!
thanks so much
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The resolution of the targets isn't at all important. You're printing solid color patches and the Spectrophotometer is making multiple measurements per patch and averaging the data.
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Hi Nirajan, I am still in the process of testing and will post more results later,
I do have a question for the experienced users on the forum and that is whether it is necessary to create a separate profile for each print resolution and mode?
Do I need a separate profile for the same ink/paper/machine combination printing at 720x1440dpi in bidirectional mode as opposed to printing at 1440x2880dpi in unidirectional mode, for example?
thanks
Neil
This issue was dealt with in this blog on the 3800.
http://www.outbackphoto.com/printinginsights/pi045/essay.html#20070206
:Niranjan
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There is a Spectral Calculator Spreadsheet on Bruce Lindbloom's website, feed it spectral data and it will provide density values.
Richard Southworth
There used to be something called "Companding Calculator" on that website - not any more, apparently for whatever reason.
Incidentally, I found this other site that has an equivalent excel formula that one can plug L value and get D.
https://sites.google.com/site/negfix/scan_dens
.......you can use the following spreadsheet's formula (substitute the $$ with the L* value):
=IF((($$+16)/116)^3>0.008856;LOG10(1/((($$+16)/116)^3));LOG10(903.292/$$))
I copy-pasted it and used some L values....cursorily it seems to give reasonable D values. I don't know the math behind it so can't say how rigorous the equation is.
:Niranjan.
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This issue was dealt with in this blog on the 3800.
http://www.outbackphoto.com/printinginsights/pi045/essay.html#20070206
Reassuring reading. However it doesn't tally with my experience. I've recently been running tests with my Epson 3880, comparing the rendering of fine detail with the settings '1440/high speed on' vs '2880/high speed off/fine detail on'. Even with a loupe, it is hard to see any difference in the presentation of fine detail (though if pressed, I'd say that the latter settings give a sightly superior result). However only a casual glance at the two prints is necessary to reveal a difference in colour. One print is warmer and more saturated than the other. So on my setup it seems that separate custom profiles will be necessary if I'm going to switch between different print driver settings (1440/2880, High Speed On/Off, Finest Detail On/Off). — I'm surprised by this, and I'm still exploring...
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Further exploring...
I've now done some more careful tests, running nozzle checks after each print to make sure nothing is amiss. The source image is a sharp Nikon D800 file, downsized to 5"x7.5" at 720ppi. The prints were examined with a loupe, and also scanned on a flatbed for closer examination. In total, four prints were made, with the following driver settings:
1. 1440 High Speed
2. 1440
3. 2800
4. 2880 Finest Detail
Observations:
1. There is no difference between prints 1 and 2. Using 'High Speed' has no negative effect on print quality.
2. From a distance, prints 3 and 4 look the same as each other, and they look different from prints 1 and 2. The difference is that they have slightly less density in the midtones. In Photoshop terms, they can be corrected to match prints 1 and 2 by adjusting the middle Levels slider from 1.00 to 0.96. Therefore on my printer I would say that switching from 1440 to 2880 has a subtle but significant effect on the tonality of the image, and to compensate for this separate profiles should be made.
3. Viewed close-up, with a loupe and (especially) with a high res flatbed scan, there is a significant difference in the rendering of fine detail between prints 3 and 4. Checking 'Finest Detail', contrary to the Epson manual, renders photographic detail more finely.
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There used to be something called "Companding Calculator" on that website - not any more, apparently for whatever reason.
I used to use the Companding Calculator for conversions between L* and Density before it was removed from Bruce Lindbloom's website. My understanding is that he had to remove it when modern browsers stopped supporting running JAVA apps in the browser for security reasons (note here that I'm talking about JAVA, NOT Javascript which is something entirely different). This was at least several years back now. In any case, as Mark pointed out in his earlier post, i1Profiler provides the density information from patch measurements and that is what I use now.
More recently I had a need to actually do the calculation myself in some code I was writing for a "Linearity Checker" application for use in linearizing my QTR/Piezography quad files. After quite a bit of googling and technical background reading, I came to understand how to do it. Lightness (L*) and Visual Density are slightly different animals and the conversion requires adjusting for those differences and human visual response characteristics. The key is first calculating reflectance (R); once you have that then density is simply -log10(R).
So, in case anyone has a need to do the calculation themselves (in code or just by hand), I've attached my short Python function that does the conversion. I've validated it with i1Profiler data and similar tools and it tracks accurately. Hope this might be useful.
Edit: Added missing minus sign in front of "log10(R)".
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I used to use the Companding Calculator for conversions between L* and Density before it was removed from Bruce Lindbloom's website. My understanding is that he had to remove it when modern browsers stopped supporting running JAVA apps in the browser for security reasons (note here that I'm talking about JAVA, NOT Javascript which is something entirely different). This was at least several years back now. In any case, as Mark pointed out in his earlier post, i1Profiler provides the density information from patch measurements and that is what I use now.
More recently I had a need to actually do the calculation myself in some code I was writing for a "Linearity Checker" application for use in linearizing my QTR/Piezography quad files. After quite a bit of googling and technical background reading, I came to understand how to do it. Lightness (L*) and Visual Density are slightly different animals and the conversion requires adjusting for those differences and human visual response characteristics. The key is first calculating reflectance (R); once you have that then density is simply log10(R).
So, in case anyone has a need to do the calculation themselves (in code or just by hand), I've attached my short Python function that does the conversion. I've validated it with i1Profiler data and similar tools and it tracks accurately. Hope this might be useful.
Never used Python so you made me look it up....learn something new everyday.... :)
Comparing your code with the Excel formula I posted earlier, I can see the first part is identical. The second part (where the condition is not met) was not immediately apparent to me as equivalent so I plugged your formula in Excel and compared with earlier results. They turned out to be identical (to at least 2 decimal points.)
By the way, the condition can be simplified as L* > 8. So there is one equation for L* above 8 and another for equal or below.
Is the Y here the same as that of the CIE XYZ fame?
:Niranjan.
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Is the Y here the same as that of the CIE XYZ fame?
Yep. In the code, "Yn" represents the max luminance tristimulus value and "Y" is the calculated value based on the L* input.
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2. From a distance, prints 3 and 4 look the same as each other, and they look different from prints 1 and 2. The difference is that they have slightly less density in the midtones. In Photoshop terms, they can be corrected to match prints 1 and 2 by adjusting the middle Levels slider from 1.00 to 0.96. Therefore on my printer I would say that switching from 1440 to 2880 has a subtle but significant effect on the tonality of the image, and to compensate for this separate profiles should be made.
Interesting!! Can I ask how you made the profile? I am wondering if the number of patches used in the test chart would have an effect? Maybe if one used a large (2000+ in i1Profiler) number of patches for the target then that would eliminate the differences you have observed?
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Interesting!! Can I ask how you made the profile? I am wondering if the number of patches used in the test chart would have an effect? Maybe if one used a large (2000+ in i1Profiler) number of patches for the target then that would eliminate the differences you have observed?
My test prints were made on Harman by Hahnemuhle Gloss FB, using a custom profile I had made several years ago. The profile chart was a standard one of about 1,000 patches, and was printed at 1440, High Speed. I will shortly send off for new profiles for this paper, and including charts for both (1) 1440, High Speed and (2) 2880, Finest Detail. I'm interested to see if separate profiles can eliminate the (subtle) differences in tonality I am seeing with the different print settings.
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Interesting!! Can I ask how you made the profile? I am wondering if the number of patches used in the test chart would have an effect? Maybe if one used a large (2000+ in i1Profiler) number of patches for the target then that would eliminate the differences you have observed?
In theory, whether or not there is a discrepancy between different modes shouldn't be affected by how the profile was made, or how accurate it was. I would think this would manifest itself regardless of what profile was used...no?
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My test prints were made on Harman by Hahnemuhle Gloss FB, using a custom profile I had made several years ago. The profile chart was a standard one of about 1,000 patches, and was printed at 1440, High Speed. I will shortly send off for new profiles for this paper, and including charts for both (1) 1440, High Speed and (2) 2880, Finest Detail. I'm interested to see if separate profiles can eliminate the (subtle) differences in tonality I am seeing with the different print settings.
Can you see a difference if you print a simple step-wedge with different conditions side by side on the same paper, I wonder.
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Can you see a difference if you print a simple step-wedge with different conditions side by side on the same paper, I wonder.
I can only assume so, if I can see the difference on two separate prints.
I'm not a colour geek, and not particularly technically minded, but I have a keen eye for subtle differences in print quality, and for me the change in tonality when switching from 1440 to 2880 is enough for me to reject the 2880 print. Getting two separate custom profiles would fix the problem, but I wonder whether I'll ever actually want to print with settings other than 1440 High Speed.
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I can only assume so, if I can see the difference on two separate prints.
I'm not a colour geek, and not particularly technically minded, but I have a keen eye for subtle differences in print quality, and for me the change in tonality when switching from 1440 to 2880 is enough for me to reject the 2880 print. Getting two separate custom profiles would fix the problem, but I wonder whether I'll ever actually want to print with settings other than 1440 High Speed.
There's no need to make any colorimetric assumptions; you have the tools to know exactly the differences in the targets used to create a profile.
1. Print out a target at 1440 and let it dry. Do the same for 2880.
2. Measure one (say 1440) two times in a row. Create a deltaE report ideally an average and with worst dE. I'd use dE2000. This report provides the noise inherent in all measuring devices. It should be well below 1.0 dE.
3. Measure the other target and now compare the dE between 1440 and 2880, keeping track of the dE noise you should subtract from the two.
Now you know exactly the differences between the two resolutions. And you know the dE noise inherent in the measuring process.
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There's no need to make any colorimetric assumptions; you have the tools to know exactly the differences in the targets used to create a profile.
I don't have the tools. (I send out for profiles.)
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I don't have the tools. (I send out for profiles.)
So you're not making printer profiles? In which case, stick to the advice from those that do 😀
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So you're not making printer profiles? In which case, stick to the advice from those that do 😀
Your advice - 'one profile for all' - doesn't work for me. If I use the same profile for 1440 and 2880 prints, the prints looks different.
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Your advice - 'one profile for all' - doesn't work for me. If I use the same profile for 1440 and 2880 prints, the prints looks different.
What you see and what is measured can differ! I'll not comment on your visual accuracy but could on actual measurements for profile creation!
"I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind".
-Lord Kelvin
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What you see and what is measured can differ! I'll not comment on your visual accuracy but could on actual measurements for profile creation!
I don't have a spectrophotometer but I do have a flatbed scanner and this confirmed my visual assessment. The 2880 print is lighter in the midtones than the 1440 print.
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I don't have a spectrophotometer but I do have a flatbed scanner and this confirmed my visual assessment. The 2880 print is lighter in the midtones than the 1440 print.
Sorry no, the scanner isn’t appropriate and IS NOT measuring.
“There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.” -Søren Kierkega
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Sorry no, the scanner isn’t appropriate and IS NOT measuring.
Why is it not appropriate? I can lock the scanner off, so it scans in a fixed state. Sure, a spectrophotometer would be handy. But if my eyes tell me the two prints are different, and my scanner supports this observation, that is sufficient for me - the 1440 and 2880 prints are different.
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Why is it not appropriate? I can lock the scanner off, so it scans in a fixed state. Sure, a spectrophotometer would be handy. But if my eyes tell me the two prints are different, and my scanner supports this observation, that is sufficient for me - the 1440 and 2880 prints are different.
For the same reasons you don't use a scanner instead of a Spectro to build printer profiles. But it's moot: you don't have the tools but do have the instructions to correctly evaluate the differences that those of us that do have done!
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For the same reasons you don't use a scanner instead of a Spectro to build printer profiles. But it's moot: you don't have the tools but do have the instructions to correctly evaluate the differences that those of us that do have done!
When I next send out for profiles I will ask the guy who makes them to give me a report of the difference between the 1440 and 2880 charts. I will be surprised if they are the same.
Just to clarify - you would expect them to be identical?
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In the meantime, here are scans of two prints, one printed at 1440dpi, the other at 2880dpi.
The 1440dpi print is darker than the 2880dpi print.
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In the meantime, here are scans of two prints, one printed at 1440dpi, the other at 2880dpi.
The 1440dpi print is darker than the 2880dpi print.
You're utterly missing the point! This discussion is about printing targets for profiles. See « Reply #18 on: July 31, 2019, 07:40:59 am (https://forum.luminous-landscape.com/index.php?topic=131486.msg1122183#msg1122183) »
NOT if one set of DPI produces a visual difference. I'd expect there would be otherwise what's the point of differing settings. You're completely missing the difference in printing solid square patches for profile creation and the instructions provided by myself and others in printing said targets and how to test all this.
I've just output 918 patches since it fits one page, on a 3880 at both 1440 and 2880. To the naked eye, the appear identical as some of us have attempted to report to you. After they dry down, I'll measure them and provide a colorimetric report as I outlined one, with the tools and knowledge should do so for analysis.
If you're sending targets for two profiles with two different resolutions, you're wasting your time, ink and paper along with whoever is measuring them. That you SEE a difference using two settings on images is utterly off topic and to be expected.
Do you understand? :o
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I am not missing the point. The visual difference I would expect when changing from 1440 to 2880 would be a slight increase in image acuity — and certainly not a change in image brightness.
Thank you for running a test.
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I am not missing the point. The visual difference I would expect when changing from 1440 to 2880 would be a slight increase in image acuity — and certainly not a change in image brightness.
As one who doesn't create profiles, or understands the results of the colorimetry of the patches used to build such profiles, or one that recognizes that the targets appear identical, yeah, you're missing the point as asked and answered in post #18. But that's OK, the person who asked about differing targets for profile creation got the correct answers from several sources.
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Have they dried yet?
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Have they dried yet?
Pigmented inks? No, they require (news flash) 24 hours for minimum deltaE colorimetric testing. At least those of us who've printed and measured targets right after output, an hour later and 24 hours later colorimetrically understand. But they still appear IDENTICAL (so much for visual testing). :-[
UltraPremGlossy first meaurment compared to 1 hour later:
dE Report
Number of Samples: 1728
Delta-E Formula dE2000
Overall - (1728 colors)
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Average dE: 1.07
Max dE: 8.59
Min dE: 0.04
StdDev dE: 0.90
Best 90% - (1554 colors)
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Average dE: 0.84
Max dE: 2.06
Min dE: 0.04
StdDev dE: 0.45
Worst 10% - (174 colors)
--------------------------------------------------
Average dE: 3.19
Max dE: 8.59
Min dE: 2.06
StdDev dE: 1.14
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UltraPremGlossy 2nd meaurment (1 hour dry down) compared to 24 hours later:
dE Report
Number of Samples: 1728
Delta-E Formula dE2000
Overall - (1728 colors)
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Average dE: 0.21
Max dE: 0.95
Min dE: 0.01
StdDev dE: 0.12
Best 90% - (1554 colors)
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Average dE: 0.18
Max dE: 0.35
Min dE: 0.01
StdDev dE: 0.08
Worst 10% - (174 colors)
--------------------------------------------------
Average dE: 0.45
Max dE: 0.95
Min dE: 0.35
StdDev dE: 0.11
--------------------------------------------------
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Perhaps my two prints will look the same when I view them tomorrow.
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In the meantime, here are scans of two prints, one printed at 1440dpi, the other at 2880dpi.
The 1440dpi print is darker than the 2880dpi print.
You shouldn't expect prints made with different settings to exactly match and, how close they are depends on individual variations in printers and how well the OEMs match the colors for different weave densities.
I have an Epson 9800 which offers settings of 1440x2880 as well as 720x1440. I always print using the same printer settings used to make the profile unless I'm just rushing something out like a large 60"x40" draft and need faster printing.
I also see a difference on the 9800 between the two modes on glossy with no other settings changed but 720x1440 -> 1440x2880. But it goes in the opposite direction you describe. The highest setting yields a 3.7 lower L* on an arbitrary gray patch. Average dE 2000 of the two targets (480 patches each) was 2.2
That's going to make a slight difference between prints viewed side by side.
Generally, follow the rule to only print using the same printer/paper/settings you made, or had made, a profile for. You might luck out using the same profile with different settings.
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Thanks Doug. Would making two custom profiles, one for each print resolution setting, fix this problem?
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Did you read this (http://www.outbackphoto.com/printinginsights/pi045/essay.html#20070206)?
02/06/2007 1400 DPI vs. 2800 DPI
According to Epson's claim, the new screening technology incorporated in the 3800 "compensates for various ink densities between resolutions - allowing for a single ICC profile to be used per media type".
In practical terms this means that you no longer need two separate custom profiles, one for printing at 1440dpi and one for printing at 2880dpi.
I never really liked the 1440dpi option of the Epson printers, other than for its speed. I always complained about it because to my eye it printed with some noticeable microbanding.
I therefore read Epson claim with much interest, and I was eager to verify it with my own measurements.
To do this I created a small color Testchart -283 color patches- and I printed it using both the 1440dpi and the 2880dpi resolution modes.
I then measured the Testcharts and compared the measurements files.
An acceptable correlation between the two measurements would be contained within delta E<1.
This limit is considered the (average) minimum distance that two colors must have for the human eye to be able to separate them.
The results are shown below:
By using different delta E formulas the results varies but the best formulas to determine small colors differences are the delta E CMC (2:1) and the newest delta E 2000. With both these formulas the Total Average is well within the 1 limit (0.82 using delta E CMC (2:1). Also the distribution of the yellow boxes (which indicate larger color differences) seems reasonably random, with the exception of the vertical column on the right, which contains low chroma colors and their difference should not be as apparent to the eye as it is to the spectrophotometer used to measure the samples.
The conclusion of this simple test is that Epson claim is right on target.
It is perfectly acceptable to use one ICC profile for both 1440 and 2880 dpi printing.
Even wet, the differences on this end thus far, between the two are an average of 0.9 which is invisible. ;)
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Did you read this (http://www.outbackphoto.com/printinginsights/pi045/essay.html#20070206)?
02/06/2007 1400 DPI vs. 2800 DPI
According to Epson's claim, the new screening technology incorporated in the 3800 "compensates for various ink densities between resolutions - allowing for a single ICC profile to be used per media type".
In practical terms this means that you no longer need two separate custom profiles, one for printing at 1440dpi and one for printing at 2880dpi.
I never really liked the 1440dpi option of the Epson printers, other than for its speed. I always complained about it because to my eye it printed with some noticeable microbanding.
I therefore read Epson claim with much interest, and I was eager to verify it with my own measurements.
To do this I created a small color Testchart -283 color patches- and I printed it using both the 1440dpi and the 2880dpi resolution modes.
I then measured the Testcharts and compared the measurements files.
An acceptable correlation between the two measurements would be contained within delta E<1.
This limit is considered the (average) minimum distance that two colors must have for the human eye to be able to separate them.
The results are shown below:
By using different delta E formulas the results varies but the best formulas to determine small colors differences are the delta E CMC (2:1) and the newest delta E 2000. With both these formulas the Total Average is well within the 1 limit (0.82 using delta E CMC (2:1). Also the distribution of the yellow boxes (which indicate larger color differences) seems reasonably random, with the exception of the vertical column on the right, which contains low chroma colors and their difference should not be as apparent to the eye as it is to the spectrophotometer used to measure the samples.
The conclusion of this simple test is that Epson claim is right on target.
It is perfectly acceptable to use one ICC profile for both 1440 and 2880 dpi printing.
Even wet, the differences on this end thus far, between the two are an average of 0.9 which is invisible. ;)
Perhaps Epson improved things with the 3880 or perhaps you have a really good one but Epson also claimed that their profiles for the 9800 could be used with any resolution. See this:
https://epson.com/faq/SPT_C595001UCM~faq-64641?faq_cat=faq-topFaqs
But, at the end and apparently in contradiction with their own statement, they added some profiles specifically for 2880 resolution. I'm not sure when the additional profiles were added but they are only a subset of papers. I still have all the Epson OEM profiles from when I bought it. There are no 2800 resolution profiles. It's one size fits all.
OTOH, even though there are clear, if slight unless viewed side by side, differences, they pale in comparison to the differences made printing the same, in gamut print, with the Canon 9500II.
But if I print the same, in gamut image with custom profiles on the 9500 and 9800 I see no difference at all unless I look for differences in bronzing and gloss differential by tilting the paper against the light.
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Did you read this (http://www.outbackphoto.com/printinginsights/pi045/essay.html#20070206)?
Yes, please see my earlier post:
https://forum.luminous-landscape.com/index.php?topic=131486.msg1122314#msg1122314
My 3880 is clearly not as well-behaved as the 3800 under discussion at Digital Outback Photo.
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Yes, please see my earlier post:
https://forum.luminous-landscape.com/index.php?topic=131486.msg1122314#msg1122314
My 3880 is clearly not as well-behaved as the 3800 under discussion at Digital Outback Photo.
But mine is.....
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3800: Match
3880 (yours): Match
3880 (mine): Don't Match
9800 (Doug's): Don't Match
I call it a draw.
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3800: Match
3880 (yours): Match
3880 (mine): Don't Match
9800 (Doug's): Don't Match
I call it a draw.
Sorry no. Looking just at the folders of spectral data files for 3880's I've profiled for customers, there are 105 there. Got 39 for the 3800. And then there's all those folks who used the profiles I built for Epson for Exhibition Fiber.
http://pixelgenius.com/epson/ (http://pixelgenius.com/epson/)
Not a draw. ;D
Nothing to do with matching. Having to do with how to print targets for creation of profiles. I'd love to suggest to customers they need multiple profiles for differing resolutions, I'd make a lot more money. But the colorimetric facts and a bit of honesty will not allow me to do so. So not matching; printing profile targets. Not what the image looks like afterwards but we've been over this ad nauseam.
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Are you saying that whilst my two prints of your test file look different (1440 is darker than 2880), if I were to print a profile target through ACPU, at 1440 and 2880, the two prints would look the same? That the driver behaves differently when hooked up to ACPU rather than Photoshop?
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Are you saying that whilst my two prints of your test file look different (1440 is darker than 2880), if I were to print a profile target through ACPU, at 1440 and 2880, the two prints would look the same? That the driver behaves differently when hooked up to ACPU rather than Photoshop?
The data (wet) already suggests this fact with respect to solid patches found on printer targets. As does the web pages referenced. I don't know why you find this colorimetric data so difficult to either accept or understand. Again, WET, the two targets measured here today have an average dE 2000 of under 1. That will be even lower but still an invisible difference tomorrow!
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I don't find the colorimetric data difficult to either accept or understand. I accept that your 3880, and the 3800 tested on the linked website, print the same whether 1440 or 2880 is selected. But my 3880 does not. I am simply trying to figure out why this is the case, and whether separate custom profiles for 1440 and 2880 would ameliorate the problem.
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I don't find the colorimetric data difficult to either accept or understand. I accept that your 3880, and the 3800 tested on the linked website, print the same whether 1440 or 2880 is selected.
FOR PRINTING SOLID COLOR PATCHES LARGE ENOUGH TO MEASURE ON A SPECTRO TO MAKE PRINTER PROFILES!!!!! That's it. I don't know, shouting or otherwise how to make this clearer and stated below (or above :o ) what you see on an image, which is composed of thousands or hundred of thousands of single color patches scattered all over an print of an image can visually differ.
The topic AGAIN IS PRINTING TARGETS FOR PROFILES. YOU DO NOT NEED TO PRINT TWO (1440/2880) NOR PRODUCE TWO PROFILES.
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FOR PRINTING SOLID COLOR PATCHES LARGE ENOUGH TO MEASURE ON A SPECTRO TO MAKE PRINTER PROFILES!!!!! That's it. I don't know, shouting or otherwise how to make this clearer and stated below (or above :o ) what you see on an image, which is composed of thousands or hundred of thousands of single color patches scattered all over an print of an image can visually differ.
The topic AGAIN IS PRINTING TARGETS FOR PROFILES. YOU DO NOT NEED TO PRINT TWO (1440/2880) NOR PRODUCE TWO PROFILES.
No need to shout. There are solid colours on the test chart I printed - e.g. the grayscale step wedge along the top. They don't print the same when I switch from 1440 to 2880.
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No need to shout. There are solid colours on the test chart I printed - e.g. the grayscale step wedge along the top. They don't print the same when I switch from 1440 to 2880.
Then something is off on your end. I'm not going to dig any deeper into your possible problems (visual or mechanical) but did answer the question asked (https://forum.luminous-landscape.com/index.php?topic=131486.msg1122149#msg1122149), consistently and upon agreement with other's who also colorimetrically tested several printers that printer targets at differing resolutions are below the threshold of a visual difference (under dE of 1).
I don’t know if you are purposely trying not to understand this, or if you are really struggling with it.
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I don’t know if you are purposely trying not to understand this, or if you are really struggling with it.
The only thing I'm struggling with is your attitude. Why so angry?
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I don't find the colorimetric data difficult to either accept or understand. I accept that your 3880, and the 3800 tested on the linked website, print the same whether 1440 or 2880 is selected. But my 3880 does not. I am simply trying to figure out why this is the case, and whether separate custom profiles for 1440 and 2880 would ameliorate the problem.
I can and do make lots of profiles since I have the instruments and software, but I can't think of a reason to print different resolutions. If I'm bothering to use a good color managed process it just never occurred to me to print with different settings than the ones I made profiles with. I have not done critical printing in lower resolution modes but color accuracy was never a major consideration in those modes and, frankly I didn't bother looking at it before.
As for other printers, like the Pro1000, for the highest accuracy they need different profiles just because the highest setting yields a dark, L*=2.0 black and the next highest only gets to 3.0. Pretty much requires two profiles though printing with Perceptual Intent or Relative with BPC, it's essentially impossible to see any difference between the two as they scale to the BP. But again, why print using a setting different than the profile was created with?
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Why so angry?
That's just another of your assumptions.
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I can and do make lots of profiles since I have the instruments and software, but I can't think of a reason to print different resolutions. If I'm bothering to use a good color managed process it just never occurred to me to print with different settings than the ones I made profiles with. I have not done critical printing in lower resolution modes but color accuracy was never a major consideration in those modes and, frankly I didn't bother looking at it before.
So you'll understand this. First, with a wet target at two resolutions, the average dE is less than 1. Now the next test would be to build a profile from each measurement target at the two resolutions (so, profile 1440 and profile 2880 as an example). Next we have to pass image data through both, again the TC918 (and the RI would play a role as would an actual image play a role but let's leave that for now). So there's going to be some rounding there. Next we need to actually print the TC918 from the two profiles and measure them again. So we start with a difference in just the two targets at two resolutions that when wet is an average of less than 1. What do you suppose the visual and measurement results will be going full circle from target to profiles to conversions to print and measurement again?
It might make an interesting time consuming experiment. But that the very first comparison averages less than 1 deltaE, and from a wet target at that, I don't see the point. But I encourage Elliot to imagine this and would love to see you test it but I've got to finish a really good Stephen King novel which I think is far better use of my time. ;D
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But again, why print using a setting different than the profile was created with?
Well, because I followed the line given by Epson and Andrew, that you only need one profile per paper.
And this led me to the bad habit of getting profiles made at the best driver settings (2880, No High Speed), when in actual fact I would be mostly printing at the fastest driver settings (1440, High Speed).
It never occurred to me that switching resolutions would affect the tonality of the image. I only discovered it yesterday when making some careful side-by-side print comparisons.
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So you'll understand this. First, with a wet target at two resolutions, the average dE is less than 1. Now the next test would be to build a profile from each measurement target at the two resolutions (so, profile 1440 and profile 2880 as an example). Next we have to pass image data through both, again the TC918 (and the RI would play a role as would an actual image play a role but let's leave that for now). So there's going to be some rounding there. Next we need to actually print the TC918 from the two profiles and measure them again. So we start with a difference in just the two targets at two resolutions that when wet is an average of less than 1. What do you suppose the visual and measurement results will be going full circle from target to profiles to conversions to print and measurement again?
It might make an interesting time consuming experiment. But that the very first comparison averages less than 1 deltaE, and from a wet target at that, I don't see the point. But I encourage Elliot to imagine this and would love to see you test it but I've got to finish a really good Stephen King novel which I think is far better use of my time. ;D
I saw this discussion and realized I'd never bothered to compare targets colorimetrically with the higher/lower resolution on the 9800.
So I ran a test and was frankly surprised at how large the average dE's were printing the same target with 720x1440 and 1440x2880. Some time back I checked the difference between bi-directional and single directional printing. One gets slightly better alignment of fine detail but the colors didn't change much at all. IIRC, well under 1 dE. So I was somewhat surprised to see the larger differences with the lower resolution mode. Especially as the canned 9800 profiles were supposed to be for any DPI.
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Well, because I followed the line given by Epson and Andrew, that you only need one profile per paper.
And this led me to the bad habit of getting profiles made at the best driver settings (2880, No High Speed), when in actual fact I would be mostly printing at the fastest driver settings (1440, High Speed).
It never occurred to me that switching resolutions would affect the tonality of the image. I only discovered it yesterday when making some careful side-by-side print comparisons.
Well, there you go. Printing at lower Q levels comes with a price, and on some printers, including yours and mine, that includes some color shift. I normally print at 1440x2880 dual direction, but sometimes print critical stuff single direction. But the latter is way slower. And that's why I had, in the past, checked for color accuracy. But I'd never bothered with the lower rez. But then I'd also never compared prints side by side. Viewed separately, I'd not noticed anything but I didn't print the same image that way so I wouldn't have noticed.
Andrew's printer is quite good and stable between the two rez modes and I had expected to see similar results. But my printer clearly has more variation.
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2880 dual direction sounds like a good balance between speed and quality. Like you, I see no change in colour or tonality when 'high speed' is toggled on and off. (But how about 'Finest Detail'? That's another puzzle!)
I'm wondering whether my print set-up might have exaggerated the differences between 1440 and 2880? Specifically, I'm printing on a third party paper (Harman by Hahnemuhle Gloss FB), with Platen Gap set to 'Wide', and Paper Thickness set to '4'. These are the commonly recommended settings for this type of paper, but perhaps they are not optimal for getting the same tonality when switching between 1440 and 2880?
Edit to add:
No, I've repeated the test with Epson Semigloss, canned profile, standard Advanced Media Control settings (Paper Thickness 3, Platen Gap Auto) and the issue persists — 2880, on my printer (Epson 3880), prints darker than 1440. This darkening can be seen most from the mid-tones down into the shadow-tones.
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Any results, Andrew?
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Any results, Andrew?
Yes, as expected, even MORE of an invisible difference after try down:
Average dE: 0.84
Max dE: 1.58
Min dE: 0.04
StdDev dE: 0.34
Once again, absolutely no reason to print TWO targets for TWO profiles; the differences in the resolution is invisible.
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Thanks for the info.
I'll be printing two targets for two profiles as my printer behaves differently to yours.
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Thanks for the info.
I'll be printing two targets for two profiles as my printer behaves differently to yours.
Knock yourself out, your paper, ink and time (and money for profiles).
What would be useful, and you can't accomplish it, would be to actually measure both targets and produce a dE report.
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Knock yourself out, your paper, ink and time (and money for profiles).
What would be useful, and you can't accomplish it, would be to actually measure both targets and produce a dE report.
I'll ask my custom profile guy to do that, and I'll report back here. (Won't be for a couple weeks.)
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I'll ask my custom profile guy to do that, and I'll report back here. (Won't be for a couple weeks.)
Just ask him to also email you the CGATs measurement files used to build the profile.
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Just ask him to also email you the CGATs measurement files used to build the profile.
I doubt I would understand it (?)
I think I just need a simple report:
Average dE, Max dE, Min dE, StdDev dE.
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I doubt I would understand it (?)
I think I just need a simple report:
Average dE, Max dE, Min dE, StdDev dE.
You would not but I would and could produce a DeltaE report from these text files.
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Oh, I see. Thanks!
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Being surprised at the relatively large dE00 differences between 1440x2880 and 720x1440 printing on my Epson 9800, I ran further tests on these with bi-directional printing: 720x720, 720x1440, 1440x2880. I also ran a comparison between 1440x2880 bidirectional and unidirectional though I had previously tested the latter and found only small differences. But it was a while ago and I didn't record the specifics. The tests confirmed my recollection that they were pretty close.
Results:
Bidirectional 1440x2880 and 720x720 / 720x1440 were both different by an average of 2.2/2.1 dE00.
Bidirectional 720x720 and 720x1440 were different by an average of 1.1 dE00.
Bidirectional 1440x2880 and unidirectional 1440x2880 differed by an average of 0.51 dE00.
One curiosity is that the average dE00 between the same RGB patches printed at different locations, a test I incorporate to check printer consistency, dropped from .19 to .13 dE00 average. OTOH, printing in that mode doubles print time and I've never seen a visual difference outside of a loupe.