Author Topic: Color Management issues?  (Read 317 times)

Offline Buzz

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Color Management issues?
« on: 2018 December 31 06:53:00 »
I was helping a friend try and get his images to look similar in PI and Photoshop. He is using Windows 10. I set up both systems to have a fully color-profiled workflow, using Adobe 1998, BP adjustment, Perceptual Rendering and so on, querying any color profile mismatch.

I opened the same 16-bit TIFF file (tagged with ProPhoto RGB) in both systems, both of which asked me what I wanted to do. In both cases, a converted to the working Adobe1998 profile.

The images were not remotely similar. Different black-point, color and gamma. The only way I could get the PS image to match the PI one, was to disable color management in PS - which makes me suspect that PI is perhaps not color managing.

I personally use a fully calibrated Mac OSX system and when I repeated the comparison between PS6 and PI, the images still do not match. Color was closer but the blackpoints were very different. I can easily screen grab the side by side to show the comparison.

I'm not sure if this a bug or not. Can anyone else verify whether they see this problem too?
regards
Chris

Offline Juan Conejero

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Re: Color Management issues?
« Reply #1 on: 2018 December 31 08:35:47 »
Hi Chris,

Yes, you have discovered a bug in version 1.8.6 of the PixInsight core application. It happens on all platforms. Thank you for detecting and reporting it.

Bug description: When the profile mismatch policy is set to "Convert to the default profile" (and, with identical results, when the policy is "Ask what to do" and the user selects the option to convert to the default profile in the Profile Mismatch dialog), the profile conversion task, although is being reported on the console, is not applied to the image being loaded (it is applied by mistake to a temporary empty image structure that is discarded). As a result, the image is not converted to the default profile, although the default profile is (incorrectly, of course) assigned.

Workaround: Select the "Keep embedded profiles" profile mismatch policy in ColorManagementSetup, load the image with its original profile, and use the ICCProfileTransformation tool to perform the profile conversion. This tool works perfectly.

This is considered a critical, maximum priority bug, so I'll release a new version of PixInsight in the next days to fix it. I am sorry for the inconvenience.

This bug is particularly painful for me, since (besides this bug) I am proud of PixInsight's color management, which I am confident is one of the best and most efficient CM implementations available.
Juan Conejero
PixInsight Development Team
http://pixinsight.com/

Offline Buzz

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Re: Color Management issues?
« Reply #2 on: 2018 December 31 08:54:11 »
Gracias Juan. It is a shame I do not work in Valencia any more. I would like to shake your hand and buy you a beer.
happy new year
regards
Chris

Offline Juan Conejero

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Re: Color Management issues?
« Reply #3 on: 2018 December 31 08:55:18 »
Hi Chris,

That would be very nice indeed. Happy 2019!
Juan Conejero
PixInsight Development Team
http://pixinsight.com/