@Mossman180,
I just used PZ wiki [pzwiki.net] to create a matching of existing in-game hair dye and paint.
Light Brown Hair Dye - Light Brown Paint
Strawberry Blonde Hair Dye (Base.HairDyeGinger) - Orange Paint
Yellow Hair Dye - Yellow Paint
And for the remaining Blonde Hair Dye, I decided to take the remaining Brown Paint. That said, I'm not sure how all of these colors really look in the game.
I don't think it's a good idea to mix up the colors in any other way, like using Brown Paint for Light Brown Hair Dye when there's Light Brown Paint, because that could confuse players too.
The colors in the picture are in order:
yellow, pink, white, black, blonde, red, strawberry blonde (gigner), light brown, blue, green.

Hey there, thanks for the mod!

Question: I accidentally used light brown hair dye on my character who's starting hair is dark brown. I thought this mod would have dark brown/brown hair dye (based on the picture), but I'm not seeing it in-game. I've checked the recipes and see that brown paint yields blonde hair dye. Is there something I'm missing, or does dark brown/brown hair dye simply not exist?

@Biggles im assuming a bucket of paint, water, and a bottle as it lists above

recipes?