Created attachment 172012 [details] Sample images and screenshots SUMMARY The thumbnails for those 16 bit tiff files that have an embedded color profile other than sRGB have incorrect colors. This does not seem to depend on which color profile is used or which application created the image. The image itself opens correctly in preview and in the editor. Only the thumbnail colors are incorrect. Same results on both windows 10 and on Linux using appimages. Digikam 8.2 works fine, but both 8.3 and 8.4 have this bug. STEPS TO REPRODUCE 1. Create a 16 bit color tiff image using a color profile other than sRGB. Using a profile with a large gamut will make the result obvious. The attachment contains sample files. 2. Load the image into digikam OBSERVED RESULT Thumbnail colors are not correct. EXPECTED RESULT Thumbnail colors should agree with digikam 8.2 thumbnail colors, and how the image is displayed in preview. SOFTWARE/OS VERSIONS Windows: 10 Qt Version: 6 Also Ubuntu with appimages, e.g., with digiKam-8.4.0-Qt6-x86-64.appimage ADDITIONAL INFORMATION From the attachment look at the screenshot "Thumbnails with digiKam-8.4.0-Qt6-x86-64.appimage". All three thumbnails should look identical, but one of them has desaturated colors. The offending image opens correctly in preview, see "Preview image with digiKam-8.4.0-Qt6-x86-64.appimage"
Git commit 3cb368201ac4a954ba4e7d07d7e645b4c3a8250a by Maik Qualmann. Committed on 26/07/2024 at 18:20. Pushed by mqualmann into branch 'master'. fix QImage 32 bit (8 bit color) from 16 bit DImg for thumbnails This issue was caused by the support of QImage 64. FIXED-IN: 8.5.0 M +1 -1 NEWS M +1 -0 core/libs/dimg/dimg.h M +19 -0 core/libs/dimg/dimg_qimage.cpp M +3 -3 core/libs/threadimageio/thumb/thumbnailcreator_engine.cpp https://invent.kde.org/graphics/digikam/-/commit/3cb368201ac4a954ba4e7d07d7e645b4c3a8250a
Note: For performance reasons, we have been saving the thumbnails in the database with color management for some time. If a digiKam version with this fix is available, the thumbnails must be recreated, either with F5 for the respective album or using the maintenance tool. Thanks for the good bug report with corresponding sample files. Maik