I am trying to mask around my green screen but I get a very dark, thin line where the mask is.
Why and what can I do about it?
System information, version information, screenshots, a description of what you do. That's what we need (not necessarily in this order).
When you say you're trying to mask, do you mean cutting out your image with a mask (rotoscoping) or do you mean using the green screen to isolate your subject (keying)?
A garbage matte, perhaps?
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