Bug 432630 - Low-contrast display of 8-bit images
Summary: Low-contrast display of 8-bit images
Status: REPORTED
Alias: None
Product: gwenview
Classification: Applications
Component: general (show other bugs)
Version: Other (add details in bug description)
Platform: Ubuntu Linux
: NOR major
Target Milestone: ---
Assignee: Gwenview Bugs
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2021-02-08 08:42 UTC by Zoltan Laszlo Ferenci
Modified: 2022-10-22 08:39 UTC (History)
3 users (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:


Attachments
comparison between the different pictures in gwenview and firefox (1.02 MB, image/jpeg)
2022-10-22 08:39 UTC, Tobias Schula
Details

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Description Zoltan Laszlo Ferenci 2021-02-08 08:42:48 UTC
SUMMARY
The color management of Gwenview results in image having lower contrast images. The problem persists for several years, over several Cannon cameras used (Cannon 30D, 10D, 5D), and several different RAW converters. 16 bit images were always working well, and I used to think that 8 bit images are just that worse and continued to export only 16-bit images, until I found that the very simple and stupid basic windows image browser shipped with Windows 7 can show the colors I wanted to see on my images even on 8-bit photos. The images are also showing well in Google Chrome, Firefox, Geegie image viewer.

Example:
https://ferenci84.s3.amazonaws.com/Compare_JPG_Exported.png

STEPS TO REPRODUCE
1. Use the images: https://ferenci84.s3.amazonaws.com/Gwenview_Bug.zip
2. Open the same image with chrome or any other browser, or in Windows image viewer and compare with one opened with gwenview.
3. Compare the colors

OBSERVED RESULT
The colors shown by gwenview is different, especially the contrast is much lower. 

EXPECTED RESULT
The colors should be the same as other viewers

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Ubuntu 18.04.5
(available in About System)
KDE Plasma Version: 5.12.9
KDE Frameworks Version: 5.44.0
Qt Version: 5.9.5
Comment 1 Tobias Schula 2022-10-22 08:39:47 UTC
Created attachment 153107 [details]
comparison between the different pictures in gwenview and firefox

It seems like you have some misconfigured color management. With my display profile (close to P3, hence the washed out colors in the screenshot) set up in kde and firefox the colors are the same in all pictures. For Firefox and Chrome it is not sufficient to set up the display profile in the color management module in kde systemsettings, you must also load it with xcalib or dispwin from the argyll package.