Is it possable to do the screen effect / like seen in Photoshop in Gem....?
I'll need to do this with webcams.
Not sure exactly how the effect actually works so maybe there is another way of setting it up...

Also does anyone know how to control the pix_levels properly. I don't get the ceiling in out stuff. I just want to kill the Red or Green in a particular gemhead.
Thanks
P

negate both of your input pictures using [# inv+ 255], do a multiply using [# *>>8], then negate the result again using [# inv+ 255]. That's what the screen effect is.