Greenscreen Red value of 0, at 32K

[Philip Powell]

Just testing and I ran across something I've never seen before. I'm not saying this is bad, just curious. I'm actually trying to figure out how it happened. We shot this test at 32K WB, with 32K lights for the "talent", and the greenscreen was lit with 32K fluorescents. What's odd is the red channel value on the greenscreen is pure zero, everywhere. I've just never seen that before. It keys fine, just a bit curious is all. Most of the time there is at least a small value there for all the primary colors at least based on all the keys I've pulled. Note, that on this jpeg, sometimes the red value goes to 1 or 2, but its just compression, in the original file, it's a solid 0.

 

[Matthew Rogers]

Maybe it's because you did a really stinkin' good greenscren?! That green looks like you took the paintbucket in photoshop and colored the background green.

Matthew

 

[conrad gaunt]

That is really interesting. Not even a little background noise? if so, wow!

 

[jbeale]

I don't think it's a case of "zero noise", but a color matrix effect. I have seen this with some green colors, some plants. Normally, even with absolute black (lens cap on) there is an offset level from zero, unless you crush the blacks in post. But with some green colors, something in the color matrix pushes one channel to zero. It can cause some strange looking images.