Thanks, I remember having read that niedegreesbelow article before, but I will go through it again. I must have mixed up something.
> "seems like black levels aren't set in my images" - what camera is it, please?
I have tested with various firmware versions from Sony A7r3 and also (if I remember correctly, I may be wrong there) with Canon 800d, 750d and others. The above statement is definitely true for A7r3, though.
> Generally, if you want quality: use floating point, apply white balance and some gamma / tone curve before demosaicking
Agreed on floating point, that will be a (simple) step ASAP. I am interested in the gamma curve statement, though, since my goal is to match about 12 different camera types as good as possible by NOT messing with "random" (excuse the term) curves. I would like to have the process as documented, stable, reproducible and non-"guessed" as I can manage.
> calculate and use appropriate forward colour transforms
This is most probably the step where I have broken something: My conversion (see above) from "camera color space" to anything more or less well-defined (sRGB is only for testing, it is NOT a "good" colorspace of course, I am targeting linear ACES in the end).
What about my question about normalization? Alex said that normalization is to be done after demosaicing, while that sounds not quite right to me (from my understanding you actually NEED to normalize - "scale to max" - the mosaic image before demosaic, but Alex said the opposite in the note mentioned above).
The main difference I see is actually about the "spreading" of the values: If we "cut"/clip the black end (lower end) and move data to the upper end (maximize values by multiplying with "maximum") normalization here must create a different set of colors. If we would normalize BEFORE cutting/clipping, that effect would be smaller. If we normalize AFTER demosaicing, using 3 channels in parallel, we'd only really change luminance, not color.
Thanks, I remember having read that niedegreesbelow article before, but I will go through it again. I must have mixed up something.
> "seems like black levels aren't set in my images" - what camera is it, please?
I have tested with various firmware versions from Sony A7r3 and also (if I remember correctly, I may be wrong there) with Canon 800d, 750d and others. The above statement is definitely true for A7r3, though.
> Generally, if you want quality: use floating point, apply white balance and some gamma / tone curve before demosaicking
Agreed on floating point, that will be a (simple) step ASAP. I am interested in the gamma curve statement, though, since my goal is to match about 12 different camera types as good as possible by NOT messing with "random" (excuse the term) curves. I would like to have the process as documented, stable, reproducible and non-"guessed" as I can manage.
> calculate and use appropriate forward colour transforms
This is most probably the step where I have broken something: My conversion (see above) from "camera color space" to anything more or less well-defined (sRGB is only for testing, it is NOT a "good" colorspace of course, I am targeting linear ACES in the end).
What about my question about normalization? Alex said that normalization is to be done after demosaicing, while that sounds not quite right to me (from my understanding you actually NEED to normalize - "scale to max" - the mosaic image before demosaic, but Alex said the opposite in the note mentioned above).
The main difference I see is actually about the "spreading" of the values: If we "cut"/clip the black end (lower end) and move data to the upper end (maximize values by multiplying with "maximum") normalization here must create a different set of colors. If we would normalize BEFORE cutting/clipping, that effect would be smaller. If we normalize AFTER demosaicing, using 3 channels in parallel, we'd only really change luminance, not color.
Or am I wrong somewhere?
Mact