green screen and match move

[Brandon Robinson]

Hey guys,

I will be working on a project where the footage is 35mm to digibeta and would like to know if you had any recommendations for how to light a green cyc where the talent has to walk on it. Their feet will be in the shot and all the green has to be replaced. Normally I would use kino supergreen, but I dont want green on the talent. What do you think?

While on subject do you think it could be better to go 35mm to DPX vs SD, there is a huge cost differential, would it help in this case?

[Will Earl]

How many VFX shots are there? Just this one or are their lot's of them. Ideally a scan would be the best way to go, you'll have an easier time compositing. Do the edit, work out which selects you need to scan (include heads and tails for each shot - typically 8, but sometimes 16 frames depending on the cut), then scan only what you need scanned.

 

Greenscreen floors are tricky to deal with, partly because of spill but mainly because it's hard to sell the contact between the actor and the cg floor. Spill can be dealt with by creating holdout mattes by using rotoscoping for those troublesome areas.

 

Try compositing this shot without using roto... :blink:

 

http://www.filmick.co.uk/2007/05/pirates-o...blue-balls.html

Edited May 31, 2007 by Will Earl

[Brandon Robinson]

there is about 4 shots, some close up, some wide enough to see the actors feet on the ground. I want to make sure I can get a good key, but lighting on the actor is very important.

[Scott Fritzshall]

A neat trick I've seen is to cover the floor with mirrored acrylic. That way you don't need to actually light the floor; it just picks up the green from the back automatically. You'll have to roto out their reflections, obviously, but that shouldn't be terribly difficult.

 

As for DPX... Hey, if you can afford it, why not? Really, though, Digibeta is pretty good, and adequate for keying. If you know that you're only finishing on SD, then I don't think you need the extra expense of DPX.