Display the colour value for any pixel in the key-in clip using the Plot tool. You can then adjust the tolerance or softness range so the pixel falls within one of the ranges. For example, plot pixels at the edges of the matte to check for softness, or plot pixels in the background to check for tolerance.
To plot a pixel's colour values:
The cursor changes to a colour picker.
A red bar appears in each colour gradient showing the colour value of the pixel.