Bug 373267

Summary: mergedimage.png has problems of rendering and color-profile in *.kra RGB 16bit files
Product: [Applications] krita Reporter: David REVOY <info>
Component: Color modelsAssignee: Krita Bugs <krita-bugs-null>
Status: RESOLVED FIXED    
Severity: normal    
Priority: NOR    
Version: 3.1 Beta   
Target Milestone: ---   
Platform: Appimage   
OS: Linux   
Latest Commit: https://commits.kde.org/krita/c8f69a1cdf2f4da11181fa492772054d576e24f4 Version Fixed In:
Sentry Crash Report:
Attachments: [*.kra file, 16bit, to reproduce the bug]

Description David REVOY 2016-12-04 22:15:27 UTC 
Created attachment 102627 [details]
[*.kra file, 16bit, to reproduce the bug]

Hi, 

I test digital-painting with RGB 16bit ClayRGB-elle-V4-srgbtrc *.kra document, and I like it! Smooth gradients, less artefact for mixing colors, precision in blending modes... But!

## The bug:
The mergedimage.png (inside the *.kra file) has problems of rendering and color-profile. It's not the same colors than my artwork.
If I export my *.kra artwork manually to *.png via Krita GUI; I obtain a 16bit ClayRGB-elle-V4-srgbtrc *.png picture. Here it's fine, color and profile is perfect, even in other apps, imagemagick, etc... But ; the extracted mergedimage.png is not the same: it's a 16bit sRGB-elle-V2-srgbtrc *.png picture with bad color rendering. This bug prevents me to use 16bit for my comic pages on Pepper&Carrot; because my renderfarm script works with the mergedimage.png from my *.kra pages. 

Screenshot: perceptual comparison of "manually exported PNG" VS "mergedimage.png" :
Eg. http://www.peppercarrot.com/extras/forum/2016-12-04_bug-report_color-profile-mergedimage.jpg 
(source *.kra file to reproduce the bug in attachment)

## Expected:
At the save time, convert mergedimage.png to 8bit sRGB-elle-V2-srgbtrc perceptual. If Krita wants to keep a 16bit mergedimage.png, then it has keep the correct colorprofile or be converted (perceptual) to sRGB-elle-V2-srgbtrc.

## Note:
For a CMYK 16Bit ISO Coated v2 300%(ECI), the mergedimage.png is correct: it's a RGB 8Bit sRGB-elle-V2-srgbtrc.icc with perceptual rendering. So both of the CMYK 16bit and the mergedimage looks the same. It means probably that the bug happens only with Krita file with this settings: RGB+16bit profiles other than sRGB-elle-V2-srgbtrc.icc.

Tested on 3.1RC appimage, ManjaroXFCE.
Comment 1 Halla Rempt 2016-12-06 10:14:56 UTC 
Git commit 817e66fd44a4fdbbeb0763cdce2a285f99348faf by Boudewijn Rempt.
Committed on 06/12/2016 at 10:14.
Pushed by rempt into branch 'krita/3.1'.
Related: bug 8

For maximum compatibility with other applications.

M  +2    -2    libs/pigment/KoColorSpace.h
M  +11   -0    libs/ui/kis_png_converter.cpp
M  +4    -0    libs/ui/kis_png_converter.h
M  +0    -6    libs/ui/kra/kis_kra_saver.cpp
M  +0    -5    plugins/impex/ora/ora_converter.cc

https://commits.kde.org/krita/817e66fd44a4fdbbeb0763cdce2a285f99348faf
Comment 2 Halla Rempt 2016-12-07 12:05:03 UTC 
Git commit c8f69a1cdf2f4da11181fa492772054d576e24f4 by Boudewijn Rempt.
Committed on 07/12/2016 at 12:04.
Pushed by rempt into branch 'rempt/impex-refactoring'.
Related: bug 8

Forward port of 817e66fd44a4fdbbeb0763cdce2a285f99348faf

M  +8    -0    libs/ui/kis_png_converter.cpp
M  +4    -0    libs/ui/kis_png_converter.h
M  +0    -6    plugins/impex/libkra/kis_kra_saver.cpp
M  +0    -5    plugins/impex/ora/ora_converter.cc
M  +0    -7    plugins/impex/ora/ora_save_context.cc

https://commits.kde.org/krita/c8f69a1cdf2f4da11181fa492772054d576e24f4
Comment 3 David REVOY 2016-12-07 13:33:48 UTC 
I tested, and it works thanks to your bug fixing ; All the step of my Pepper&Carrot renderfarm now display the same colors and consistent color-management pipeline if I use 16bit, CMYK or other files as source *.kra files: the mergedimage.png is consistent. http://www.peppercarrot.com/extras/temp/2016-12-07_Selection_001.jpg , Thank you Boud!