1. Grabbed a limited palette off of lospec.com and a reference face off of thispersondoesnotexist.com
2. Drew in Blender’s Grease Pencil with vertex colors and max jitter and randomness
3. Use smaller and smaller brushes with less and less randomness
4. Blur the colors in Vertex Paint, then keep painting
5. Throw a bunch of modifiers on it

Grease Pencil is not necessarily the best choice for impressionist painting. The swatch interface means you can’t color pick like other programs, and the vector nature of grease pencil doesn’t lend itself toward blended edges. But there’s a lot of upside for it! Sculpt mode moves stroke points, which means edits work a lot cleaner than something like Photoshop’s liquefy tool. Plus, the footprint left behind with strokes and points mean the painting is great fodder for animation and modifiers. On this here stack I played with the Build, Dot Dash, and Thickness modifiers.