User guide

KeylightThe Foundry

ADVANCED KEYING

Inside & Outside Mattes

will display which pixels use a replace method. Those pixels who use a

replace method because the Screen Matte processing tools modified the

transparency will be green, whilst those pixels whose transparency was

modified by the inside matte will be blue. See the Status on page 23.

There are four options to the Replace Method, these are:

1. None - the despilled image is left untouched if the alpha is modified.

2. Source - the image will have a corresponding amount of the original pixel

(screen colour and all) reintroduced/removed if the alpha is changed.

3. Hard Colour - the despilled image has a corresponding amount of the

replace colour added for any increase in alpha.

4. Soft Colour - the despilled image has a corresponding amount of the

replace colour added for any increase in alpha, however, it attempts to

modulate the luminance of the resulting pixel so that it matches the

original pixel. This will give a more subtle result than the Hard Colour

option.

Inside & Outside

Mattes

If you can’t adequately improve the Screen Matte using the Clip Levels, you

can pull another matte to identify the pixels you definitely want to be

foreground or background. The Inside Matte makes the foreground less

transparent and the Outside Matte is used to clean up the background that

might have bits of the foreground showing through.

These mattes should normally be softened and eroded to blend into the

Screen Matte and not interfere with the foreground edges.

Inside and Outside mattes are picked using a different technique to the

Screen Matte. To create an inside matte for example, select the Inside PPG.

It helps when first picking the foreground to switch the Render menu to

show the Combined Matte. Now click and drag parts of the foreground to

Figure 52. Green Screen. Figure 53. Status after pulling the Screen

Colour.