You can try to deflicker the green screen and then pull the key. I believe there is a deflicker macro in the cookbook or you can use the pixel analyzer and use an expression. If it is various colors at different frames, then it probably won't work. Or you can try to average the footage, if it isn't moving to much and then pull the key. Or you can check the channels for contrast, deflicker the chosen channel, then pull a luma key. Obviously this depends on your foreground footage minus the screen. Yikes, too bad it was shot this way. Sounds tough.
Catherine
QUOTE(world @ 04/15/06, 04:13 PM) [snapback]234399[/snapback]
hi everybody...
just got some footage which i have to key. the problem i'm having is that the value of the green screen changes over time because the production crew was shining different colored lights on the foreground element (and consequently the green screen). as a result, there are frames which change from green to yellow in the same area. is there another way of keying this without having to do a separate key for each color or keyframing the screen color?
any advice would be much appreciated. thanks!