Hello i have a well rounded question that anyone could take a stab at. We are attempting to take blood squibs and cover them with green screen material and then put that also on a green screen and shoot it with them blowing towards the camera. Obviously we just want the squib's blood explosion so we can insert it where ever we need. Now i know movies like sky captain, kong, etc have extensive action keyed on a green/blue screen without getting bleeding, blur, etc. Any one have any ideas? What would be my best bet? I attempted to key our first test in after effects and no dice, the green either bled or most of the explosion detail was lost! Thanks guys!
You may be over-thinking this one: a luma key using a white or black background may be plenty good for this. That's what they seem to use a lot for flame and smoke stock. Dropping the blood onto a sheet of glass with the green material under it, you could shoot that from above or below the glass.