how to make holdout matte?

[Blade Borge]

reading the after effects studio techniques book, talks about holdout mattes for green screen, doesn't exactly say how to make one...

[CaptainMench]

First, understand what a holdout mask or matte does for you. Say you have a green screen shot but something on the shirt of the person reacts to the keying filter you are using and puts a 'hole' in the shirt...

Ok...

First, duplicate the original image and put on the layer above the original.

Turn it OFF

Key the layer two.

Look for 'holes'...

Turn on the layer one duplicated original and use the MASK tool (pen) and draw around that shape. You might need to invert depending on what happens then.

If your original layer is keyframed to move make sure you copy the keyframes to the other layer too (or just parent it back).

Hope that makes sense.

Good luck,

CaptM

[Blade Borge]

inescapably clear, thank you sir!