I am bringing in gfx, let’s just say an endcard with alpha. Basically the alpha is a window but there is big block white text over the rest of the endcard. The files are tiff, png, mov, whatever. When I place it on the timeline and enable the comp tab all looks fine. But once it renders the big block white text gets an odd black edge to it. It is subtle but definitely noticeable. This is the area that is just graphic and not the window. I have changed all the tabs separately in the comp menu and rendered and every time , the black edge. Timeline is 16x9, gfx are 16x9 and everything is 10 bit. Happens with all social sizes as well. I hope this all makes sense. Any thoughts?
Have you double checked that your graphic doesn’t have illegal/NAN colour values? Have you tried a clamp on the graphic prior to compositing it over the background? What colourspace is your graphic and what colourspace is the media you are adding it to?Out of interest, if you change the setup to 16bit float does the issue still occur?
Also, have you tried to premultiply your graphic (multiplying The RGB by the alpha) prior to comping it on? Or you may even need to do the reverse and divide with the alpha as you may have a double mult happening. Not in front of a system right now.
Is the black of your alpha 0? Every once in a while I get a matte with the blacks raised a miniscule amount so that it looks black to the eye, but makes a visible artifact in the comp.