Every colour has three dials: hue (which colour), value (how light or dark) and intensity (how vivid or muted). Most mixing advice is about the first two. Jewel tones and earth tones are the two ends of the third: jewel tones are dark and intense; earth tones are muted, knocked back from bright.
Jewel tones: darken without dulling
Emerald, sapphire, amethyst, ruby: deep, saturated colours, and the combination of dark value with strong colour is what makes them rich. A colour that is merely dark (navy, brown) or merely bright (lemon) isn’t a jewel tone. The challenge is making a colour darker without losing intensity, and both black and complements dull a colour as they darken it.
Instead, darken with a darker neighbour on the wheel: deepen a green with blue, a red with violet, a violet with blue. Keep yellow away from purples and blues; it dulls them towards brown.
- Jewel tones read best against neutrals or dark backgrounds. Put them next to each other and they compete.
- Glazed thinly over a light ground they glow like stained glass.
- A white highlight next to a jewel tone makes it look deeper.
- Phthalo Green, Dioxazine Purple and Quinacridone Magenta make jewel tones almost straight from the tube.
Earth tones: dull without darkening
Earth tones are the colours of soil, clay, bark and dry grass: ochres, siennas, umbers, terracottas and olives. They sit in the warm half of the wheel and they are never at full brightness. Historically they were the first pigments, dug from the ground as iron oxides, and you can still buy them as tubes. You can also mix every one of them.
Start with the bright version of the hue, then add a little of its complement. The complement cancels some of the brightness without turning the mix grey or black. Add it in small steps: it’s far easier to dull a colour a bit more than to brighten one you’ve taken too far.
- Landscapes and still life: most real-world colour is far less saturated than it looks.
- A calm earthy base makes a few bright accents look brighter.
- A thin wash of sienna or ochre as an underpainting gives a warm glow under later layers.