I always feel like a low rent chess player speaking with a grandmaster when I am speaking with Brecht, but I believe there is some inaccurate information here.
So here goes... On Feb 17, 2012 12:42 PM, "Brecht Van Lommel" <brechtvanlom...@pandora.be> wrote: > The problem is that it's not actually true that this is always the > correct thing to do. [...] > If you're compositing over a black background, leaving this option off > will give the exact correct result. To the best of my knowledge, this statement is fundamentally incorrect. In all non-linear associated alpha (premultiplied) formats, the RGB values are in fact associating both emission / occlusion and a color component. The net sum of this is that _all_ linearizations on assocaited alpha RGB non-linear values are incorrect[1], irregardless of the background you intend to perform the over upon. Why? Because the RGB values themselves, directly out of the file, are exactly as explained above; a hybrid associated combination of occlusion / emission and RGB color. I will do my best to explain this in images if I can find some time today. As to how to determine default behavior, it is not easy because we are faced with both non-linear (EG: TIFF) and linear formats (EG: EXR) as well as the combination of associated versus unassociated alpha. The inherent nature of Blender's image loading code with correct flagging and granularity is the issue. With respect and hopefully not looking like a complete fool here, TJS [1] It should be considered more coincidence that 0.0 and 1.0 happen to be identical in pre-linearization and post-linearization, rather than any degree of overlapping logic. _______________________________________________ Bf-committers mailing list Bf-committers@blender.org http://lists.blender.org/mailman/listinfo/bf-committers