I have been using Aces on my last couple of projects, all going relatively smoothly so far.
My issue arises when converting artwork to Aces, which needs to be premultiplied.
In Nuke Studio, I will always get ugly edges when converting to aces and then masking by the alpha on the timeline. I get the same issue when trying to convert and render via nuke. The problem happens because the colour values (for white) are going from 1 (in normal rec project) to ~16 for Aces. However the alpha is not changing, and so semi-transparent areas are reacting differently when pre-multiplied
Aces - Colour = 16 * alpha .5 = final picture value 8
rec - Colour = 1 * alpha .5 = final picture value .5
See the attached screenshot to see what I am talking about. Note that this screen shot has a viewing Lut of ‘standard’ rec709, and so the bottom legal line looks correct, and how I want my Aces artwork to look. I can not do it this way though as the ACEs_rec709 lut needs to be applied for the footage to look correct.
In the past I have had my masters timeline change back to rec709, and so all legals etc work as expected, but I don’t want to be forced to work this way and would rather keep AcesCg the whole way through, to avoid changing viewing Luts/export types etc
Any ideas or thoughts are much appreciated!