Generate the Screen Matte

Generate the Screen Matte

A few decisions are absolutely essential in Keylight and the
rest are essentially compensatory. I have seen artists spend
literally days on keys that sadly could be improved in under
an hour with a different approach.
The core of Keylight is screen matte generation, and the
most essential step is choosing the exact color to key. From
that, Keylight makes weighted comparisons between its
saturation and hue and that of each pixel, as detailed in
From this, you see that the ideal background is
distinct and saturated.

COMPARED TO SCREEN COLOR, PIXEL IS                                     KEYLIGHT WILL

Of a different hue                                                                                   Consider it foreground, making it
                                                                                                               opaque
Of a similar hue and
more saturated                                                                                         Key it out completely, making it
                                                                                                                transparent
Of a similar hue, but
less saturated                                                                                          Subtract a mathematically weighted
                                                                                                           amount of the screen color and make
                                                                                                              it semitransparent





This section details the other tools that contribute to the
screen matte:
. Screen Gain emphasizes the saturation of the background
pixels
. Screen Balance delineates the background hue from
the other primary colors.
. Bias is for color-correction.