Black and white make grey, but a flat one that looks slightly blue and sits apart from everything around it. Painters mix greys from colour instead: two complements, or all three primaries, balanced until no colour wins, then lightened with white. A grey made that way contains real pigments, so you can nudge it warmer or cooler to sit with the rest of the painting.
With the default paints, every grey and black in the library is mixed with no black at all.
Black is the simplest colour to mix
A mixed black looks darker than tube black once it’s on the canvas, because it is full of colour rather than flat. To see which way your black leans, lighten a dab with white: the grey it makes shows the hidden colour at once.
Why not just add black?
Black darkens a colour by killing it. It also shifts the hue, and with yellow it shifts it completely: yellow plus black is olive green, which is why ‘add black to darken’ gives so many muddy paintings.
Warm, cool and neutral
- Neutral grey: balance the complements until no hue shows, then add white.
- Warm greys and greige: let the orange or red side win slightly.
- Cool greys, blue-grey and slate: let the blue win. Slate Grey is 10 parts white, 5 Phthalo Blue, 3 Cadmium Red.
- Charcoal and gunmetal: the same mixes with little or no white.
- Check a grey against a pure white and a pure black; it’s easy to think a grey is neutral when it leans warm.
Using neutrals
- Neutrals are the quiet background every bright colour needs. A painting without them often looks garish.
- Mix your neutrals from the same paints as the rest of the painting, and they’ll sit in harmony with your colours.
- Pale greys make convincing skies, mist and shadows on white objects.
- Blue blacks are good for night skies and deep shadows; warm blacks for hair, wood and tree trunks.