Crystal Vision
Using Safire 3
The Chroma Key Gain (CKG)
Min Clip
and
Max Clip
controls are used to clip the
key at its minimum and maximum levels. Both these controls are set
automatically by Auto Setup but may need adjusting.
Min Clip
is mainly used to
reduce any small amounts of key level in foreground object areas causing
breakthrough of the BG picture. Increasing the
Min Clip
value will force lower key
levels to zero. Shadows can also be accentuated by raising
Min Clip
.
Max Clip
is used to increase the overall gain of the key signal, removing
variations to give an even result. The following picture is the Output Key with
Max
Clip
set to a low value – although there are no variations in key in backdrop
areas, fine hair detail has been lost. Set
Max Clip
to as high a value as possible.
Low values of
Max Clip
also change the shape of the key causing edges to be
more noticeable in the composite output.
Additional Controls
To illustrate more advanced Safire 3 features it is necessary to use a more
challenging FG signal. The backdrop is unevenly lit and has shadows and
reflections that may or may not be wanted. The model is also wearing a shiny
black jacket that tends to reflect and cause an unwanted key.
Safire 3 User Manual R1.3
57
24 March 2017