The Three-Pass Method

The Three-Pass Method

This breakdown will work with any software keyer, but it’s
especially helpful if you’re trying to get the most out of
Keylight.
1. Rename the Keylight effect by selecting it and pressing
the Return key. Rename it Keylight gMatte.
The fi rst goal is to create a background matte that is
100% transparent and outside of all edge detail by several
pixels. To do so, follow these steps:
a. In Keylight Status or Combined Matte view (depending
on your preference), raise Clip Black just
enough to remove gray pixels from the background
in Status view, then lower the Clip White setting just
above the same number.
b. Important step: set View to Intermediate Result.
c. If necessary, choke this matte further to eliminate
tracking markers and other small bits of noise. You
can lower the Screen Shrink/Grow setting (under
Screen Matte in Keylight) or apply a Simple Choker
effect and raise the Choke Matte number. Quick
and dirty is fi ne here.

d. Whether or not you’ve choked the matte, the most
essential step is to spread it until it’s well outside
the foreground edge. You can apply Simple Choker
and lower the Choke Matte setting to a negative
value, quite possibly in the double digits, even using
a second instance if the maximum setting of –100 is
reached without completely exceeding the foreground
boundary.
e. Garbage matte any items in the background that
have not disappeared and hand-animate the matte
as needed (refer back to .
You should see a generous blue (or green) buffer
around the foreground edge.
2. Duplicate the layer and rename it Core. Reset the
Simple Choker effects and solo the layer.
This matte fi lls in all holes inside the matte edge without
coming close to overlapping that edge. To create
this layer
a. In Keylight Status or Combined Matte view (your
preference), lower Clip White until the foreground
is completely opaque. Raise Clip Black to a value
just below the same number.
b. If necessary, spread this matte to eliminate foreground
holes by raising the Screen Shrink/Grow
setting (under Screen Matte in Keylight). You
can also lower the Choke Matte setting in Simple
Choker to a negative value.

c. Whether or not you’ve spread the matte, choke it
until it’s well inside the foreground edge. If there
was no spread operation, use Screen Shrink/Grow
in Keylight; otherwise, use Simple Choker.
d. Add a layer and garbage matte; any remaining holes
resulting from extra-stubborn shiny, refl ective costumes
or props.
e. Soften this layer as needed with a Fast Blur; with
all three layers on, toggle the cMatte on and off
to make sure it has little or no effect on the edge
.
3. Apply a second instance of Keylight on the layer containing
the gmatte. If you like, rename this effect Keylight
Edge. You have isolated the edge to the maximum
extent possible .
Now just work on that edge layer—starting over with its
key, if you want, because it’s now a much simpler problem
that demands the lightest possible touch. Your goal should
be to use three controls only to refi ne it: Screen Colour,

Clip Black, and Clip White. If possible, do not adjust
Screen Gain.
This is not the furthest you can go to break down a color
keyed matte; problematic footage will require further steps,
described in the following section.