Re: some help with poorly lit blue screen

I agree with all the comments here about the difficulties of keying with DV. PITA. I have run into these issues as well so i feel your pain.

Here's my suggestion for what it's worth. Once you get your best key (Keylight's the best - I see you are using it too) dup the layer and remove the key effect. On this layer draw a garbage mask around the subject. Not so close to the edges that it becomes a rotoscope job but loosely inside and only in the trouble areas. Most of the time we're talking about an interview subject and they don't move around a bunch. Feather the mask a bit too. Now key frame the shape as needed to follow the subtle head bobs. I've had to do this lots usually due to bad lighting or because the subject was wearing something with a chroma key color on it.

I find placing the garbage mask beneath the chroma key can yield the best results but most of the time it won't matter.