what bugs me is if you look at a chromaticity diagram of the CIELUV color space for a given lightness, you can see that greens and yellows are much closer to total desaturation than violets and reds. blue’s in the middle, with lots of room in deep blue, but cyan’s just as cramped as green.
 
if your character’s green and yellow, even at 100% saturation they’ll be duller in color than red and violet ponies, to human eyes at least. that’s one reason why sunlight looks white, even though it’s yellow, since all the blue photons got scattered by our atmosphere. and if you decrease saturation by a teeny bit, it has a bigger effect on green/yellow/cyan, and a lesser effect on blue/violet/red.
 
I don’t get how much you’re supposed to decrease the saturation I guess. all my attempts just make them look boring and grey. unless they start out red and violet, of course.

Diamond “Diamond Tiara” Tiara
 
(Diamond Tiara)

hey don’t forget tag my part
 
https://www.deviantart.com/luckreza8/art/Mlp-Fim-New-Fluttershy-happy-vector-665082138  
https://www.deviantart.com/luckreza8/art/Mlp-Fim-Starlight-Glimmer-vector-2-704070881