Blender AgX in darktable (proof of concept)

[kofa (István Kovács)]

@flannelhead

What darktable is missing is some sort of a “guard rail” that catches values that go outside the target medium boundary (values below 0 and above 1). Blender’s AgX includes also the guard rail transformation.

I’ll try to have a look.

I’ve also played with gamut compression, you may have seen that topic. E.g.

Tone mapping and gamut compression articles

OK. Some gamut compression charts. We are rotating in 30-degree steps around the D65 white point xy coordinates, so each of these contains 12 groups of bands. For each angle and Y luminance value: we take the xy coordinates at the edge of the Rec2020 gamut (this is determined via a simple search), and note its distance from the white point (maxDistanceRec2020) Then, we shorten that distance according to a fixed multiplier; each chart has its own, starting from 40% and going up to 100%, in st…