gradient maps (Patreon)

i use them when the colours arent going right when im painting, they can probably do way more but this is how i use them generally :>

(this page is also handy: https://www.clip-studio.com/site/gd_en/csp/userguide/csp_userguide/500_menu/500_menu_layer_shikichou_gradation.htm?rhsearch=gradient%20map&rhsyns=%20 )