I created a gradient map set available for purchase on Gumroad here. The tutorial above shows how I start out using gradient maps to create the base of my illustrations to then add more colours and depth. It’s a technique I’ve used for years, but have never seen a tutorial cover it.
Combining gradient maps with comic flats made in Peltmade Multifill is a quick way to feel out a drawing. I’d often use them for designing fill-ins for pieces in the past too.