So I have this clip. White outlines, the background of the image are varied, but contains different shades of brown mainly. The outlines are lined over the background, but the background is also in the surface within the outlines (the subtance).
There is also a a black cross shape that goes through the whole screen (also beneath the outlines).
A couple seconds in (playing the clip), the shape within the outlines change color to a beige-black.
The problem is, I've been playing around with different ways to remove whatever's on the outside of the outlines. But the colors of the substance within (that appears within the couple of seconds), matches the background too much. So when I color key for instance, I remove some of the substance that I want to keep within the outlines.
I've obviously tried point mattes, but they're not accurate enough, and important parts of the shape will disappear.
I'm thinking this can be done manually, and gradually (applying different effects throughout), but that will take a lot of time.
In short: How do you cut out a shape accurately, from a background that has the same colors as the substance in the shape?
Thanks