Thumbnails not color-managed + severely distorted shadow tonality for thumbs, previews

Elle Stone ellestone at
Sat Nov 18 14:15:23 GMT 2017

On 11/17/2017 03:51 PM, Marcel Wiesweg wrote:
> I have no precise opinion, but essentially thought of a user accessible switch
> in the setup.

That would be wonderful!

> Performance must be optimized for the >>90% of users with the limited use
> cases images in sRGB or Adobe RGB or RAWs -> no monitor profile or one created
> with argyll cms / dispcal.

Yes, absolutely the default settings should reflect whatever seems to be 
the most common use case.

Having a user option to disable the LCMS optimizations will make digiKam 
useable for people who want to see proper tonality for linear gamma 
images. I suppose a similar option could be in showFoto? Or would the 
one switch cover both softwares?

Through no fault of digiKam's, there is currently no support in digiKam 
for GIMP-2.9 XCF files - see GIMP bug report - the time to compress 
and save an embedded png is not inconsirable, which is a factor not 
currently discussed in the bug report.

So to work around the lack of support for 2.9 XCF files, I made png 
"sidecar files" for all my XCF files. This required also modifying the 
kimageformats source code to not recognize XCF files, and then compiling 
and installing the modified code, to keep digiKam from trying to read 
the XCF files and then crashing.

Modifying the digiKam source code to not use the LCMS optimazations and 
then compiling and installing the modified code turned out to be very 
easy to do - the last time I tried to compile digiKam was several years 
ago and it wasn't easy, so thank you! to whoever has made compiling 
digiKam so much easier than it used to be.

GIMP-2.9 has been my main image editor for painting and photography for 
the last five years, so I've accumulated a lot of GIMP 2.9 XCF files. 
DigiKam has been my DAM software since around 2007. It's a huge relief 
to finally be able to use digiKam for sorting/selecting/viewing the XCF 
"sidecar files" and for opening the actual XCF files. I'll probably keep 
using this "sidecar" approach even after there is digiKam support for 
2.9 (or more likely 2.10) XCF files.


and thank you for digiKam


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