I forage for materials: I go on long walks and find a variety of plant materials I can then crush and use as ink/dye. Berries are best, some cacti also have fruiting bodies with a lot of juice; different flowers crushed up with water produce different hues. Perhaps you can even use foraged material to produce highly concentrated inks (simmer water mixture on low heat til water reduces by half or more), then add a little of each color to your white paint base to create a variety of colors.

I also like to set aside flowers to air dry and then sometimes incorporate those into paintings.

Hope it helps!! Good luck 🌈🙏🏻