Following your instructions in the RawTherapee thread that we hijacked
Assigning the custom camera profile from disk produces expected results - the colors look correct, matching colors produced by other raw processors.
Adding a colorspace layer and selecting “Rec2020-elle-V4-g10.icc” as the ICC profile produces unpleasant and oversaturated colors. The default (upper) checked box is the “apply” box, which I would suggest changing the label to “assign” as that’s what it seems to be doing.
Unchecking the “apply” (upper) box and instead checking the “assign” (lower) box produces the correct colors that should result from converting from the camera input profile to “Rec2020-elle-V4-g10.icc”. So this box’s label should be changed to “convert”.
Using the default rawproc settings (removing “rawproc.conf” and then restarting rawproc), I saved the resulting image to disk as a tiff. Opening the resulting tiff in GIMP-CCE, the image was in dcraw’s incorrectly-made ICC sRGB profile with the D65 white point. The image colors look to me as if:
Somehow “Rec2020-elle-V4-g10.icc” is being used as the camera input profile, instead of the dcraw camera-specific profile made from the adobe_coeff table.
Somehow a curve is applied to the image file to produce altered tonality, by dcraw? maybe the Rec709 curve? maybe the sRGB curve? Maybe via an ICC profile assignment somewhere?
The resulting “wrong colors and wrong tonality” image is converted to the built-in dcraw sRGB profile and saved to disk.
Something other than 2 above could be happening to produce the final image tonality, but I’m pretty sure - just by looking at colors in the raw file displayed in the rawproc image window - that somehow “Rec2020-elle-V4-g10.icc” is by default being used as the camera input profile, instead of the appropriate “standard” dcraw ICC profile from the adobe_coeff table.
As an aside, may I suggest making the user interface backgrounds (119,119,119) by default? A pure white background makes it difficult to judge colors and tonality.
Also, is it possible to use black point compensation when sending the image to the monitor screen?