Lens Cast Calibration (LCC) #19697
Description
Is your feature request related to a problem? Please describe.
This tool is commonly used for negative inversions and doesn't exist in darktable. This tool can correct in one pass the combination of the vignetting of the lens (if it's not already in the database) and the irregularities of the (back)light used, both in luminance and chrominance. Negadoctor is a fantastic tool but right now we can't feed it with a perfectly corrected picture.
Describe the solution you'd like
Ideally, it should work like in LR or C1 I guess. Based on one reference picture, the module creates a lens cast correction that should be the base for further adjustments in the pipeline. It corrects the luminance and chrominance of the whole picture to make it look like a plain color. It should ignore small dust and scratches.
Alternatives
Nothing very practical. Right now, the best alternative is to load your reference picture, then of course to activate the lens correction if it exists, to check if it doesn't over/under corrects vignetting, to further correct it with some negative or positive vignetting, up to the point where the picture seems uniform or "good enough".
Additional context
It may have other uses than the negative inversion, I don't know.
2 screenshots of the effect in Capture One, in one click :
Reference picture, without LCC :
The same picture, with LCC :
