Re: HMI and Green screen

Actually a 1/4 minus green ...and 1/8 CTO is subtle. Considering the amount of green light already rimming the subject (via bounce off the screen) the complementary pink serves to negate that. I've actually used full minus green in my backlights occasionally, depending on how much green spill is polluting the subject. Obviously the amber would do the same complementary thing if you're keying with a blue screen.
I like adding a "hint" of CTO to my backlights all the time -- whether I'm chromakeying or not -- depending on the color tonality of the subject's hair (and hair dye!). It adds warmth to people with white hair, vibrancy to people with blond or sandy blond hair, and a warm reflection (instead of a cold white refelction) off the head of someone with black, dead hair. It's all subjective, and a matter of personal taste however.

DS