Limited Palette: Harmony Through Mixing

When a picture feels restless, it's rarely because colours are missing – usually it's because there are too many. Every tube you take straight from the pot onto the paper brings its own pigment with it, and twelve different pigments in one sketch add up to twelve different moods. Opaque paint is especially unforgiving here, because the areas are large and the colours strong. The solution is surprisingly simple: you cut back to five tubes and mix everything yourself.

The five tubes

You need a titanium white, a mid yellow, a mid red, ultramarine blue and burnt sienna. With acrylics and gouache, white is the tube that empties fastest, so buy it in the larger size. The other four will last many months in small tubes. Together this set costs you roughly CHF 40 to 60 – considerably less than a set of twelve, and you learn incomparably more along the way.

What's missing catches your eye first: no black, no green, no brown, no grey. That's exactly the point. You mix these four colours from the five tubes, and because you mix them, they belong together.

Grey is the most common city colour

Ultramarine plus burnt sienna plus white gives you the whole range of greys you need in a city. The ratio of the two chromatic colours decides the temperature: if ultramarine dominates, the grey turns cool and bluish, like a concrete wall in shadow or a roof under clouds. If burnt sienna dominates, it becomes warm and slightly reddish, like a rendered wall in sunlight. And the white only determines how light the grey becomes, not its character.

Practising pays off, because while mixing you learn to work both sliders independently: set the temperature first, then the lightness with white. Change both at once and you end up in mud.

Green, façades, asphalt

Green comes from yellow plus ultramarine. Mixed straight, it's usually too acid for a city sketch – trees in front of grey buildings are more muted than you'd think. A tiny dab of red takes the glare out of the green, because red is green's complementary colour and lowers the saturation without making the colour grey. Use really very little, a brush tip's worth is enough.

Façades come from burnt sienna plus white: that gives you the sandstone, terracotta and ochre tones of old-town walls, ranging from strong red-brown to pale rosé depending on how much white you add. A touch of yellow pushes the tone towards ochre, a touch of ultramarine towards dusty pink.

Asphalt is ultramarine plus burnt sienna without white. This mixture goes almost black but stays alive, because depending on the ratio it tips towards blue-grey or brown-black. In a city sketch you practically never need to go darker than this mixture. Black from the tube would make your shadows flat and dead.

The mother tone connects everything

Now comes the trick that turns five tubes into a harmonious picture: you repeat one colour in every mixture. Choose burnt sienna, for example, and add a small amount of it to every mixture on your palette – into the green, into the grey, even into the sky blue. This colour running through everything is called the mother tone. It shifts all the tones in the same direction, and your eye reads that as shared light. In cool, grey weather you take ultramarine as the mother tone instead; in evening sun, rather the red.

Values before hue

More important than the exact hue is the value – that is, how light or dark an area is. If you get the value right, your eye forgives a surprisingly off hue: a wall may have turned out too pink or too grey, as long as it stays lighter than the roof and darker than the sky. If you get the value wrong, the most beautiful hue won't help, the picture stays flat. So when in doubt, check with your eyes squinted: the colours then disappear and only the light-dark gradation remains visible.

Organising the palette

Give your palette a fixed order so you can work it blind. White goes at the top, well away from everything else, because you need it most often and in the largest quantity. Put the warm colours on the left – yellow, red and burnt sienna – and the cool one on the right, that is ultramarine. The middle stays free as a mixing area. That way you automatically reach for the right thing, even when you're working standing up and looking at the subject instead of the palette. And because the pure colours stay at the edge, they don't contaminate each other.

Exercise

Find a spot with a view of a town square, a junction or a courtyard and set yourself 20 minutes. Take only the five tubes. For the first five minutes you paint nothing at all: you mix six greys from ultramarine, burnt sienna and white, three warm and three cool, each at a different lightness. Put them as small patches along the edge of your page and note in pencil what's in them, for example "lots of sienna, little ultra, medium white". In the remaining 15 minutes you paint the square – and for every area you start with one of your six greys before shifting it, if needed, towards façade or tree with yellow or red.

Key points

Five tubes give you every city colour, twelve give you restlessness. One mother tone in every mixture turns separate colours into a picture. And if you have to choose between value and hue, always go for the value.