Wrong color profile conversion when saving a photo which has ICC profile

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simohno
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Joined: Sun Jan 03, 2021 2:47 pm

Wrong color profile conversion when saving a photo which has ICC profile

Post by simohno »

Hello

I noticed that when a photo which is ICC-tagged (meaning it has an "ICC profile" data structure in the metadata, for example Adobe RGB 1998) is edited in XNV and then exported with File > Save As, when in the Options window the option "Preserve ICC profile" is checked, something really annoying happens for a photographer point of view:
The colours are converted to the monitor profile set in the Settings (in my case, that registered at the OS level, option "System"), and the monitor profile is (correctly) associated to the exported file.

So, instead of preserving the photo's colour profile (in the example, Adobe RGB), XNView makes an unwanted conversion, hence clipping/compressing the colours that are outside the monitor's gamut. The colours keep displayed correctly, but the fact that a photo gets described with a monitor profile is really annoying and is something "sacrilegious" in photography. I am starting using GIMP for every small edit, even if XNView is quicker.

I suppose this is an unintended behaviour, and it contrasts with the good colour managing workflow rules, so I reported it among the Bugs and in my opinion needs urgent revision as follows: the conversion of RGB values to the monitor profile is to do for the visualizing purpose only, after every edit, and the operations on the file have to be done in the original colour space! Thus preserving that colour space when saving.


Important side note: the File > Export module, contrarily to Save As > Options, lacks the possibility to incorporate an ICC profile, the current is discarded and colours are not converted to sRGB -> upon the next opening the image is wrongly interpreted as sRGB and the colours are wrong.
Ideally I would like to have an option to convert to a specified colour space in the JPEG format Options tab (e.g. to convert to sRGB for web publication).

Many thanks. Also, developers, please check my Suggestions also about colour management in XNView in the other forum page.
As a reference for corrections you can experiment with the GIMP (GNU) which behaves correctly with colour profiles, both on file and on monitor side. At present, XNView is great for photographic work only until you start using any bit of color management...... :?


XNV MP version 0.98.1 on Windows 10 20H2 64 bit
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xnview
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Re: Wrong color profile conversion when saving a photo which has ICC profile

Post by xnview »

yes, when loading a file with ICC profile, image data are changed and if you save it, you'll have new datas
Pierre.
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