Deep Dive into colors

Doing a deep dive to get colors for a quilt that goes from dark to light within a spectrum  I would like some more mediums but my stash just does not have any more so I am going with what I got...This is a use stash only project to challenge my color perspective without buying anything. Now to cut strips, I am going to use my newly acquired Accuquilt for some.Wonder if the red cutting board is tainting my "eye" of these colors..??