Before the 19th century, painters didn’t have to worry about selecting a palette of paints from a huge array of those available. There were only a few pigments available, so painters had to make do with what they could get. If you wanted an opaque red, you had vermilion and, well, vermilion. So you learned how to get everything you could out of that pigment. You didn’t complain that it was a bit too orange for your taste, because your choices were vermilion and nothing. In addition, you had a couple of bright blues (both of which were incredibly expensive), a couple dull blues, a transparent violet-red, a green that had to be used carefully or it would turn black, an orange, a dull-ish yellow, one white, some variations on carbon black, and some earth colors. That’s mostly it, and you only had that many colors if you could afford them and lived someplace where there was enough trade to obtain them.
Go to a museum some time and look at some paintings from the Renaissance. Notice any absence of color? Dullness? Inability to obtain mixtures that convey a sense of reality? Muddiness? Poor color harmony? Unrealistic flesh tones? No? Many of those paintings were done with six or seven total pigments. Not pigments carefully selected to create an optimal palette from among hundreds of colors available in in an art store, but six or seven pigments selected from maybe ten or twelve that the artist could get. And yet they made some of the most gorgeous paintings ever created.
If you like the way paintings from before 1800 look, one option is to select a palette of colors that replicates those available then. So here is a simple palette that is similar to what was available in Western Europe before the new synthetic pigments began to be discovered in the late 1700’s.
White: lead white was about it. If you want to simulate the color and opacity (not the handling properties) of lead white, mix titanium white and zinc white at about 50/50, then add a tiny touch of yellow ochre.
Black: usually bone black (now called “ivory” black), lamp black, or vine black.
Red: genuine vermilion, which you can simulate with cadmium red light. Red lake, which you can simulate with rose madder or alizarin crimson. Minium (red lead) which you can simulate with cadmium orange mixed with cadmium red light.
Blue: mineral ultramarine, which you can simulate with modern synthetic ultramarine (if you want to simulate cheaper grades of this incredibly expensive pigment, add some white and black). Azurite, which you can simulate with cobalt blue. Indigo, which you can simulate with Prussian blue mixed 50/50 with black.
Yellow: lead tin yellow, which you can simulate with a 50/50 mix of cadmium yellow light and yellow ochre. Later on, Naples yellow gradually replaced lead tin yellow. It is similar, but more like 2 parts cadmium yellow light to 3 parts yellow ochre.
Green: greens were usually mixed from ultramarine or azurite and lead tin yellow or Naples yellow. They also had copper green (used only sometimes, since it was known to turn brown unless isolated between layers of varnish), which can be simulated with viridian.
Violet: was usually mixed with red lake and a blue.
Orange: was usually mixed with vermilion and lead tin yellow or Naples yellow.
Earths: a wide range of earths were available, depending on where the artist lived. These included equivalents to modern raw sienna, burnt sienna, raw umber, burnt umber, yellow ochre, red ochre, green earth, black earth, brown earth. They also sometimes used malachite, which you can simulate with 1 part viridian to 5 parts white.
There were a few others used from time to time, but these were the common ones. Most artists didn’t use all of these.
Try using this palette for a few paintings. You’ll get a much better sense of how “Old Masters” did their color mixing.