Has anyone used the photo filter in Photoshop? Edit > Adjustments > Photo Filter...
It produces a really nice image tint that I've been unable to reproduce with blending modes. Has anyone got any idea of the pixel maths behind this filter? - So I can build a shader based on it.
It seems to basically be a luminosity preserving colour tint.
Has variables: Color, Amount and Preserve Luminosity.
Any ideas?
Filters (in light) are multiplicative, as in:
red_filter = ( 1 , 0 , 0 ) * color
I don't think any blend-modes exist for it, since any transparent overlay with that system would darken the image to some degree.