I have a strange behavior of the “red color fraction” with a picture of sunflowers. OOC-JPG looks very near to perception at time picture taken. RAW development in darktable fails the second sigmoid is activated.
Setup:
On Debian 12, darktable 5.2.1 and working with a Canon 70D
Color profile set up XAtom due to a darktable-cmstest message.
Standard sigmoid scene related workflow (but result with flimic RGB almost the same).
Looking at the second Screenshot „with simgmoid“:
the Upper picture Shows the raw file - the yellow in the flower is gone into an non natural red tone.
The lower picture (jpg) gives a good Impression of the scene during capture.
This „Color Shift“ happens the moment sigmoid or filmic RGB are activated.
I hope this explains better.
Because Sigmoid (must be activated as part of the scene referred workflow) is recovering the highlight (you have some pixels clipped) and preserving colors.
If you don’t like the color preserving done by Sigmoid, just lower the corresponding slider. At 50% it may look better to you.
Thanks for the OOC JPEG. Here is the GIMP saturation map. The histogram is set to the 254-255 … more or less 100% saturation. The root problem seems to be in the raw capture which makes it difficult for any application to produce good scene petals RGB.
Note that 3.9 percentile (2.3 MP) are blown or close to blown. HSV saturation is blown (100%) when one or more channels are forced to zero - in this case, the blue channel. That means that maybe 3% of the pixels in your OOC are bichromatic (only red and green) which is not right for natural stuff like flower petals.
