Comparing papers: surprising results

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I saw a video that John Paul Caponigro has put out where he pulls up the original image in a window and then pulls up the soft-proofed i mage

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That's what I do. That's the normal way soft proofing is displayed in LR.

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According to the LR Proofing algorithm, the Museum Etching paper has a wider gamut than the other two papers which have identical gamut as far as I can tell.

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Just to make sure I understand--are you referring to LR showing out-of-gamut regions when you turn out the output gamut warning?

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Originally Posted by DanK

Just to make sure I understand--are you referring to LR showing out-of-gamut regions when you turn out the output gamut warning?

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The short answer is yes.
I opened the original image in the develop module, checked the softproof box, turned on the show print out of gamut warning and sequentially selected the three paper profiles. The out of gamut warning (red) area was smaller for the Museum Etching than the other two. The more surprising thing is that the proof copy of the luster and glossy papers were identical. I confirmed this by loading the two on separate layers in photoshop and used the "difference" blending mode. The result was a completely black picture confirming that the difference between the two was zero throughout. Comparing either one with the proof copy ot the Museum Etching did show differences. I am at a loss to explain why papers of different types from two companies would match exactly.

Hmm. This suggests that the OOG warnings aren't paper specific, which I suppose isn't all that surprising, given how many papers there are. Perhaps they have one algorithm for most coated papers and a given printer/ink combination. that would be more of an approximation than I would like. Perhaps someone has written and explanation of how this works.

It would be interesting to try this same exercise for a variety of uncoated papers, as those presumably vary more in gamut. Over the coming weeks, I intend to test a variety of matte and fine art papers from Canson , Hahnemuehle, and Moab, and Ill keep an eye out for this.

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Originally Posted by Round Tuit

I am at a loss to explain why papers of different types from two companies would match exactly.

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It could be that two different companies are companies are selling exactly the same paper. This would suggest that the profiles would be identical.

Epson and Canon do not own any paper manufacturing so buy their papers from third party manufacturers. The Harman line from Ilford was produced by Hahnemühle. One of the printers who has been mentoring me has suggested he finds no difference between Canson Infinity Baryta Photographique and Epson Legacy Baryta.

I believe that this is true across the board and even companies that do manufacture paper could be marketing papers from other suppliers under their own branding to fill out their product lines.

What you have found here is not at all surprising.

I've never used Harman Glossy Fibre Art Warmtone, which is actually a Hahnemuehle paper, but from the specs, I don't think it is the same paper as Canson Baryta Photographique. The Canson is slightly heavier (310 vs. 300 gsm), and it is not a warm-tone paper. If their specs are to be believed, the CIE whiteness of the Canson is 99 and that of the Harmon is 91. The Canson is listed as "very low" OBA, while the Harmon has no OBAs. That might be a reference to the barium sulfate coating on the Canson, as the Harman specs make no mention of baryta.

Andre, do the two papers (unprinted) look different?

The two papers are very different. The Canson Infinity Baryta Photographique is a smooth luster paper with a very fine texture. The Harman Gloss Art Fibre Warmtone has a medium texture, is glossy and has a slight beige tint.
I have come to the conclusion that there is something wrong with the way LR5 handles the display of OOG colours. I have plotted the gamut of the Hahnemhule Museum Etching and of the Harman paper and the gamut of the Museum Etching is definitely smaller than the gamut of the Harman which makes sense to me. I was unable to plot the gamut of the Canson because it uses an ICC V4 profile rather than an ICC V2 but I suspect that it too would be larger than the Museum Etching but somewhat smaller than the glossy Harman paper.
I don't know for sure but I suspect that LR uses low precision arithmetic when figuring out the differences in gamut and that the rounding errors may be larger than the actual differences.
In any case, the visual differences between the prints is very subtle and may be more related to differences in brightness and contrast than to gamut issues. When in doubt, I would rely on test prints to make my final decision.

André - how are you plotting the printer / paper gamut? This sounds quite interesting.

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Originally Posted by Round Tuit

When in doubt, I would rely on test prints to make my final decision.

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That has always been my approach as well.

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Originally Posted by Manfred M

André - how are you plotting the printer / paper gamut? This sounds quite interesting.

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I'm interested too ...

I don't know how André does it but I use ColorThink which, apart from plotting image gamuts, can open profiles and plot their gamuts in various formats, e.g. 2D, 3D, xyY, L*a*b* etc. It can also overlay plots for easy comparison.

https://www.chromix.com/colorthink/
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I use a program called iccgamut for plotting icc profiles and tiffgamut for plotting the gamut of a tiff file. Both are part of a free extensive suite of colour management programs called argyll cms. The suite is not for the faint of heart as it is all command line interface but the documentation is excellent. Unfortunately, it does not handle ICC Version 4 profile yet. Both programs generate a HTML file that uses the W3DCOM capabilities of modern web browsers to do the actual plotting in 3D. The generated plots can be rotated in space.

Thanks André - I remember looking at Argyll a number of years ago and it sounds like the user friendliness has not changed at all. My test images and print proofs tell me a lot more about how the paper performs than the gamut models, so I will keep on plugging with my current methods.

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Originally Posted by Round Tuit

I use a program called iccgamut for plotting icc profiles and tiffgamut for plotting the gamut of a tiff file. Both are part of a free extensive suite of colour management programs called argyll cms. The suite is not for the faint of heart as it is all command line interface but the documentation is excellent. Unfortunately, it does not handle ICC Version 4 profile yet. Both programs generate a HTML file that uses the W3DCOM capabilities of modern web browsers to do the actual plotting in 3D. The generated plots can be rotated in space.

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Thanks for the info, André.

Some really good stuff there for those whose understand technical stuff ... :D

V4 seems a bit like DNG in that it has yet to take over the planet. It's been years since it first appeared on the ICC site.