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Author Topic: Measuring Canon Pro1000 profile quality--what does good look like?  (Read 422 times)

Prospero

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Hi All,

I am very new to color management, so do let me know, if I should post my questions elsewhere and/or differently.

I am trying to obtain a basic understanding of the typical quality of canned profiles (mainly using Hahnemühle papers) and those I am creating myself.

Although none of the apps I tried (X-Rite or Datacolor) provide any functionality to support this use case, and none of the many forums I checked provide any instructions, I do find this useful, in order to decide, how good a canned profile is and if it is worth the resources to create a custom one, to check if my profiles/setup are up to typical quality standards (nothing seriously "broken"), if/how my setup is degrading over time, or to better understand how much effort (patches, ink, paper) is justifiable to create my own profiles.

I am very eager to learn, what I might be missing in trying to pursue such tests, as neither the developers of the major calibration tools nor anybody in the many forums I checked appear to find this useful.  I am aware that average statistical errors don't tell you much about the strengths, weaknesses, and visual appearance of a profile to the human eye.  So I am also looking at test images to check how the profiles perform on real images.  Still, having some absolute and objective metrics in addition should be very helpful to keep tabs.

I have come up with some basic tests and would like to get some opinions on the approach and results, before I head off spending much more paper and ink.

I am using a Canon Pro-1000, i1Pro3+, i1Profiler App, PhotoShop, and the BabelColor Patch Tool.
 
My approach to measuring the quality of profiles:

- Choose a list of patches with known Lab values.  For the below tests I took the DigitalColorChecker_M0 set of 140 patches that comes with the PatchTool, mainly because this fits on one A4 page with the i1Pro3+, the colors should virtually all be within gamut, and I could not find any other representative set of similar size
- Save a 16bit TIFF target image in Lab space out of PatchTool
- Load the image in PhotoShop and double check that the Lab values still match the original ones shown in PatchTool
- Print target image from PhotoShop with absolute colorimetric intent
- Scan print with i1Pro3+ from PatchTool
- Run the comparison function in PatchTool to obtain the deltaE* errors for each patch and some additional statistics

Following this process, I tested the Hahnemühle original canned profile for their Photo Luster paper, as well as a simple initial one I created as a "baseline" with just 293 patches.

See the picture below for the results.  The left side shows the results for the canned profile, the right side for my customer one.  I am a bit surprised of the size of the errors: 

For the canned Hahnemühle profile, more than 101 of the 140 patches have a dE higher than 4, half of them higher than 5.5, and the worst 14 patches an error of more than 29. 

For my simple custom profile it looks considerably better, but still not great.  50% of patches are above dE of 2 and the worst 10% are over 5.9.  Maybe this is just due to 293 patches not being sufficient. 

Thanks in advance for sharing your experience on what good really looks like!

Markus
« Last Edit: April 10, 2021, 08:16:17 am by Prospero »
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MichaelKoerner

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Re: Measuring Canon Pro1000 profile quality--what does good look like?
« Reply #1 on: April 10, 2021, 03:03:12 pm »

Hi Markus,

I had a related experience some time ago with Hahnemühle Museum Etching on an Epson SC-P800, see this post.

Apart from all possible user errors I'd say: Well, that's possible - and a good reason for using custom-made profiles.

Some of my learnings:
  • Visual comparison rules over measured data. That means: Printer test files, like those from Andrew or Keith Cooper, should be used regularly, so you get to know them well on different papers.
  • That said, a verification tool as used in RIPs when measuring contract proofs does more or less the same as the "hand made" workflow you established with PatchTool (which I salute you for :-)). There is an online solution I never tried myself (as I use an EFI RIP) but could make your life easier: https://www.colorcheck-online.de/
  • Calibration, aka "bringing your machine into a defined, repeatable state" is important before(!) profiling, but often considered unnecessary in the inkjet world. I don't think so: You can "reevaluate" all your different profiles with one basic recalibration. In my case, I use ColorBase, which is an Epson tool - don't know what Canon offers you likewise.
  • AFAIK you already researched about finding proper media settings, which is laudable - but are you sure you used the media settings recommended by Hahnemühle when using their profile?

Best regards, Michael

Doug Gray

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Re: Measuring Canon Pro1000 profile quality--what does good look like?
« Reply #2 on: April 10, 2021, 03:21:14 pm »

Profile verification is most meaningful when testing profiles you make. That way you are using the same spectro, M0,1, or 2, and certainty over printer and paper settings. There can be large differences in spectro readings between models and manufacturers. And even some smaller ones between the same models.

First thing to check is what M you should use. Measure the paper's white point with your i1Pro3 and check it against the paper's white from the profile. Use the M that is closest.  These days lots of profiles are made with M2 instead of M0.

As for color set. Use Patchtool to generate a set of values that are in gamut for the profile you use.

Tools->Gamut Tools->List Gen. Put the paper profile in the target profile. Then generate a list. Adjust the Pitch higher or lower so you get the max number easily checked with the i1Pro3+.
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Alan Goldhammer

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Re: Measuring Canon Pro1000 profile quality--what does good look like?
« Reply #3 on: April 13, 2021, 09:43:49 am »


Visual comparison rules over measured data. That means: Printer test files, like those from Andrew or Keith Cooper, should be used regularly, so you get to know them well on different papers.
This is the most important factor!!!  I've been doing profiling for myself and friends for the past 12 years using ArgyllCMS.  As long as I am careful reading patches, their is a very low color error in individual patches as judged by an Excel spreadsheet of the readings compared to what is expected.  As long at the average error is low, the profile is acceptable from a 'technical' perspective.  Argyll provides a number of tools for profile examination that I use but for me the key point is how colors are rendered when printed.  AS noted there are a number of printer evaluation test files that can be used.  My favorite is the one from Outback Photo.
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MichaelKoerner

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Re: Measuring Canon Pro1000 profile quality--what does good look like?
« Reply #4 on: April 14, 2021, 03:30:28 am »

My favorite is the one from Outback Photo.

+1, it contains all you need for profound evaluation in a (in my view) very pleasing arrangement. I print all my paper samples with this image.
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