Updated: Apr 21, 2021
I can paint almost any image with primary colors by mixing. However, a fuller palette is more convenient. This fuller palette (and totally non-toxic) is comprised of cool and warm colors. I don't add green so to avoid artificial greens...unless that is what I want. I add other more convenient colors like browns and black (primarily to mix a deep green).
Note that as a paint is lightened, it may change from cool to warm or in reverse. Also, the coolness or warmth of a color depends on its adjacent color. Occasionally, I'll use other colors but be warned that some of them have toxic pigments and must be handled with care. See the chart and image for my safe choice of cool/warm artists oil paint colors by M. Graham, an almost no odor walnut-oil-based paint. Go to my YouTube Channel, Simona's Fine Arts, and see Part 1 and 2 on Mixing Colors. In the description, you can get links to these products on Amazon.