XnView Software

XnView: MP 1.6.3 64 bit
OS: Mac Ventura 13.6.3 64bit
Monitor: Wide gamut (imac 2017)

Thumbnails generated by XnViewMP for jpgs saved by cameras set to use AdobeRGB color space are less colorful (slightly less saturated?) than they should be.

Note: However, thumbnails generated by XnViewMP for jpgs generated by Photoshop in AdobeRGB colour space (which have AdobeRGB Profile embedded) are now rendered correctly (this was fixed in 1.6.3). This suggests that XnView generates AdobeRGB thumbnails correctly if the jpg contains an embedded AdobeRGB profile. But, if the embedded profile isn't present and the jpg is only tagged as AdobeRGB ("Uncalibrated" EXIFIFD tag with interopindex) the jpg is perhaps being treated as if it contains sRGB data?

To reproduce:
1. Download these two files
https://www.dropbox.com/scl/fi/mfar8baj ... e2hm7&dl=0
https://www.dropbox.com/scl/fi/a9evc2xb ... n7fvi&dl=0
These are images of the same test chart taken with a Lumix G100 camera set to use sRGB and then aRGB color space.

2. Set XnView to generate a thumbnails from the images and inspect color rendering.

I wouldn't expect the sRGB and aRGB thumbnails to look identical, but they should be pretty similar (because most colours in the chart lie within sRGB space). Note how thumbnails of the same files are rendered in Adobe Bridge compared to XnView MP in the following screenshot.
https://www.dropbox.com/scl/fi/3t7ta974 ... zw6fv&dl=0

I see the same issue when using a Sony RX100 camera set to sRGB and then AdobeRGB color space.

OK I've created some better test images to more clearly illustrate the problem.

Image 1 - I synthesised a jpg of a Passport Colorchecker target in Adobe RGB color space and saved it with embedded AdobeRGB color profile.
https://www.dropbox.com/scl/fi/iu2jxjpa ... 65ec8&dl=0

Image 2 - I then stripped all the metadata from Image 1
https://www.dropbox.com/scl/fi/16vn0sgw ... kbqed&dl=0

3 - I then inserted typical Camera metadata from my Lumix G100 when set to use AdobeRGB color space into Image 2.
https://www.dropbox.com/scl/fi/a8ksqqkk ... rgwzi&dl=0. This file doesn't have an embedded color profile, but does have EXIF tags that indicate the data is aRGB.

The correct rendering of these three images is therefore as follows;
Images 1 and 3 rendered identically with nice bright colours.
Image 2 will be rendered dull (aRGB data rendered as sRGB).

Adobe Bridge gets this right, but XnView doesn't render the thumbnail for image 3 correctly - as shown by this screenshot.



The screenshot can be downloaded from here. https://www.dropbox.com/scl/fi/0hhkleew ... a1zin&dl=0

In XnView MP 1.6.3 the thumbnail rendering of Image 3 is incorrect (it is dull). It's been rendered the same as image 2 because XnView thumbnail generation code has not identified the data as AdobeRGB and has rendered it as sRGB instead. Interestingly XnView MP's full screen rendering of all 3 images is correct.

Hope that helps.

Thanks to your detailed description I can reproduce the problem.

This problem is supposed to be fixed in XnView MP 1.6.4. Please check and confirm the bug fix here.

xnview wrote: Tue Jan 09, 2024 10:00 am This problem is supposed to be fixed in XnView MP 1.6.4. Please check and confirm the bug fix here.

I confirm that, on my wide gamut iMac Retina with XnViewMP 1.6.4, the thumbnails of aRGB jpg images with tag only (typical of in camera jpgs) and with tag + embedded profile are both now rendered correctly.

EXCELLENT - Thanks