Unpremultiplied Render Option?

[joelly3d]

Are there any plans to add an unpremultiplied checkbox for Max VRay in the future? Sometimes edge fringe problems are unavoidable when doing print renders seemingly because of the edge pre-multiplication. Even with AA filtering off, there are still some artifacts. It should affect all passes. Often when re-building a render from passes in photoshop, the artifacts will appear. Defringe sort of works, but corrected source would be best.
Has this been discussed as a possible add?
Thoughts?
-Joel

[Morbid Angel]

Have you tried unpremultiplying the frames in post like in nuke?

[joelly3d]

No, we don't have Nuke here, and when doing print work we just run everything right into Photoshop using ProExr. Just seems like it should be easy enough to implement for the future.

[Morbid Angel]

I recall playing around with unpremultiplication during rendering...but I can't remember how I did it, but I was able to output unpremulted renders and premult them in comp. The idea is to remove the alpha from all your passes and do all the color corrections without the alpha and then reapply alpha at the end. Not too sure how this would work with photoshop though...