[Bf-committers] Color Unpremultiply

[Matt Ebb]

On Sun, Feb 19, 2012 at 4:15 PM, Brecht Van Lommel
<brechtvanlommel at pandora.be> wrote:
>
> So for me this is more a question of what the best default is, if
> having this enabled for premultiplied alpha images is considered
> better then in principle I have no problem if this gets enabled by
> default. However there is an extra issue which is that currently we
> have no way to know if the image is premultiplied or not. For render
> output maybe to some extent, but even then compositing can change the
> kind of alpha that the render has.

Well, the image viewer kind of 'implies' that output images should be
premultiplied (otherwise they'll look bad), but this is probably also
the fault of there being no option to choose how to interpret imagery
that you're viewing, to correct accordingly.

Even so, it would make sense to me that the output option would be
aligned with whatever the viewer does (by default at least), so that
if the viewer assumes premultiplied images by default (which in turn
encourages artists to premultiply their imagery so it looks correct in
the viewer) then it may be a good assumption that the output is
premultiplied too, and divide accordingly. This is just talking
defaults though - the option is still required.

Matt