A great look at using the vector scope in After Effects where Andrew Devis continues his tutorial series on color correction. The vector Scope is part of the color finesse plugin that ships with After Effects, although a similar vector scope can be found in a bevy of other 3rd party plugins as well where all of this would still apply.
“The vectorscope is a powerful tool to help users get a graphical representation of the chrominance values of their footage instead of just having to rely on their eyes because – as we all know – our eyes don’t always tell us the whole truth when it comes to dealing with color! Because the vectorscope is somewhat hidden in AE, it is sometimes overlooked, so in this tutorial, Andrew Devis shows how to find, set-up and use the vectorscope in AE to look at whole images as well as specific regions of interest.”