Scene-referred editing with PhotoFlow

[gez (Public Enemy Nº 2)]

@ggbutcher

I think that the colorspace gamut has to match the reference colorspace gamut in the OCIO.config file, or match a “to-reference” transform.

Correct.

@ggbutcher

The TIFF used for input in @gez’s Blender demo produced using dcraw has sRGB primaries assigned, and the corresponding data, per the man page. That would work with Rec709-referenced OCIO configs, as the color primaries in both specifications are the same.

That’s correct, although as we already discussed is not mandatory for every case.
We propose sticking to rec.709 primaries at least for these first tests for the sake of simplicity, as it will allow trying existing OCIO configs (like Filmic Blender) without further modifications.
Otherwise, a different configuration should be created (either changing the reference to rec.2020 or producing a transform for linear rec.2020 to the existing rec.709 reference) which adds an extra layer of complexity that is better to leave aside for the moment, until everything else is properly understood.

@Carmelo_DrRaw

@gez @troy_s - is this reasoning correct, or am I missing something?

It looks ok, yes. Just keep in mind that if the ubounded gamut thing is involved, you’d want to mark that checkbox for clipping negatives.
Does the raw developer use libraw?
On the other hand, the black compensation on save seems something you don’t want activated.

Regarding the lens correction, theoretically I think it’s fine, but you’ll have to make sure that the operation is designed for scene-referred RGB and won’t mess with your light ratios.