Hey AE experts - I'm thinking of purchasing AE for a project, here's a question regarding matting (and I'm not seeking a tutorial, just want to know if it's possible):

Say you're pulling a luma or color key, and you have the key dialed in to where you're happy. Then you want to do something radical to the footage that affects the color - say keyframe it so the saturation fades out or brightness, color balance, etc. changes.

Since the matte produced by the keying process is based on things like color & luma, will your key then fall apart? Or is there a way to lock the key or separate it from the footage (but still aligned with the footage spatially and temporally) so it remains a useable mask.

My real expertise is in Photoshop; the Photoshop metaphor would be making a mask and then converting it to an adjustment layer or layer mask, a free-standing thing independent of the data on the image layer - is there an AE function like that?

THANKS! - MC

Hi Michael,
AE allows you to add an 'Adjustment layer' too...
Stick it at the top of the stack and you should be able to do what you suggest.

Gareth

Effects in AE are in an order from top to bottom. If you add a Luma Key, and then a color balance effect it will not change your key at all. You could even move the color effect up to apply BEFORE the Luma Key if you wish -and things may change. So the order in which you have the effects can affect the image in different ways. So you have nothing to worry about.

thanks guys!