Why Am I Mixing Mud Colors?

Female painter working on painting in studio
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"I am new to painting. I am attempting to paint an abstract using the following paints: Golden Fluid Acrylic quinacridone gold and quinacridone crimson. ... These two colors are mixing nicely, but every time I try to add in turquoise phthalo, I start getting mud. What would work without turning my painting to mud?" -- Lavenderlady33881


Why would mixing two colors together not produce mud, but mixing in a third does? The answer lies in what is actually in each of those colors. Are they single pigment colors, or are they already mixtures?

The more pigments in a mixture, the faster you'll get to browns and grays (or tertiary colors). Single pigment colors mixed together decrease the rate at which colors get muddied. The information printed on a paint tube label should tell you what pigment(s) is in a color. you what pigment(s) is in a color.

Phthalo Turquoise is a mixture of a blue and green pigment, not a single pigment. It's PB15 plus PG7. (Color Index Numbers explained.) Quinacridone crimson is a mixture of PR206 and PR202. Quinacridone gold is a mixture of PO48 and PY150. So quinacridone crimson plus quinacridone gold is already four pigments. Adding in phthalo turquoise makes is six pigments in the mix.

Blue plus orange means you're mixing complementary colors, a standard formula for mixing a brown. You've got blue and orange in these paint colors, so brown is inevitable. It doesn't matter if you're physically mixing the colors or doing it through glazing (optical mixing).

As for which colors will or won't make mud, I think it's best to paint up your own color chart from the paint colors you've got to see what happens when you mix a particular one with any of the others. It helps internalize what each color will do, a step on the way for this information to become instinctive, as well as creating a reference chart. Print out this color mixing chart and start exploring the properties of your colors.