I Could Really Use A Color Chart

I'm separating out a set of very minor color variations in the Prexie set, and am having trouble distinguish which stamp is the minor color v the major color.

For example:

Scott # 805 Which stamp is the darker one, the "Bister Brown" or the "Buff"

Scott # 812 Which stamp is the darker one, the "Sepia" or the "Violet Brown"

Scott #823 Which stamp is the darker one, the "Brown Carmine" or the "Rose Brown"?

Scott #825 Which stamp is the darker one, the "Bright Blue Green" or the "Deep Blue Green"

By name only, the darker hue is;
Bister
Violet
Brown
Deep
A suggestion, leave 'em alone for a day or so, a fresh look may help.