3 ms·
The thing about LUTs is that it's only mathematically valid if you know the type of data the "input" is--and I'm not just talking about oh is it an 8 bit image
by hatsunearu 5y ago
The thing about LUTs is that it's only mathematically valid if you know the type of data the "input" is--and I'm not just talking about oh is it an 8 bit image or a 12 bit image.
It needs to be aware of the color space and EOTF (an extended idea of "gamma")--which is why LUTs are only used in very controlled scenarios (e.g. for videography, the input color settings are fully detailed, for example Sony's slog, so the LUT is a reproducible, mathematically sound operation)
"RAW" photos from cameras are what we call linear color space, where the RGB values correspond linearly to the amount of light received by each photosite. If you try to use a LUT designed for RAW on an sRGB JPEG image, you're gonna have some problems, at least without screwing with the color space.
It's why I kind of gave up on trying to use LUTs in photo editing, it's just so unreliable.