Chroma and luma keying – tolerance correction
As was shown in the previous picture, widening the scope with the White level function usually makes the plane, that formerly had a uniform black color, return to the light gray color scale.
In this case, to correct this gray, the two following functions from Tolerance Correction section are necessary.
Click on the button Tolerance Correction to open the tolerance settings window.
The first function – Luminance – improves the structure of the white mask’s uniform color.
The second function – Color – means returning to a single structure of the black background.
In particular, it improves visibility of an object, when there is a big difference in luminance between the object and the background. In this case, semitransparent objects, like a glass or eyeglasses, become more distinct.
Color function also fulfills a different task. It allows you to eliminate unnatural contours when you disable Show Alpha Matte and return to the actual image. You can remove these contours by improving the limit value between the keyed color and the object.