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In this case, in order to adjust the grayness, two further functions from the
Tolerance
correction
section are needed. The first one is called
Color
and its use leads to the
restoration to a uniform black structure of the background.
The
Color
slider
The other one,
Luminance
, improves the structure of the uniform colour of the white mask.
The
Luminance
slider
It improves in particular the visibility of an object in the case of a significant difference in
luminance between the background and the object. This means that semi-transparent
objects, e.g. a glass or glasses, become more distinct. A view ‘before’ and ‘after’ an
adjustment is presented in the two pictures below.
A view before a
Luminance
adjustment
A view after a
Luminance
adjustment
The
Color
function is also used to bring about another effect. Once the option
Show alpha
matte
is switched off and the real picture is restored, it is possible to eliminate unnatural
outlines.
This can be done by improving the border value between the keyed colour and the
object.
A view before a
Color
adjustment
A view after a
Color
adjustment