Mixing Olive and Terracotta from Six Tubes
A student has six tubes: Prussian blue, lemon yellow, vermilion, burnt sienna, titanium white and ivory black. The task is a 25 × 35 cm folk-style panel with an olive-green leaf border and a dusty terracotta background. The first try gives a sharp blue-green and a pinkish red; the teacher says the colours are 'too fresh' and do not sit together. The student proposes adding ivory black to both 'to make them dull' and white to the green 'to make it lighter'. The paper is handmade and absorbs water quickly; colours dry about one shade lighter than they look wet. There is enough paint for two more trials only. The panel must be finished in 90 minutes, and the border must remain distinguishable from the background at 2 metres.
1. Give a mixing procedure for the olive green and the dusty terracotta, including approximate proportions and the reason for each addition.
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Olive green: Start with lemon yellow (about 2 parts). Add Prussian blue in tiny increments - roughly 1/8 part - until the mixture is a yellow-green, not a blue-green. Prussian blue is very strong, so add it to the yellow, never the reverse. Then add burnt sienna in pinches, about 1/10 part. Burnt sienna is a warm earth red-orange, near-complementary to green; it lowers saturation and shifts the green toward olive. Stop while the green is still recognisable.
Dusty terracotta: Start with burnt sienna (2 parts) and vermilion (1 part). Add a very small amount of Prussian blue - about 1/20 part - to knock back the pinkness; blue is complementary to the orange-red and neutralises it. Add titanium white in small increments (about 1/2 to 1 part) only to reach the target value. Because the paper dries lighter, mix both colours slightly darker and stronger than the target. Test on the same handmade paper, not on a white palette.
Contrast at 2 m: make the border darker and cooler than the background, or lighter and cooler, but not equal in value. Olive green against terracotta already differs in temperature; reinforce it with a value difference.
2. Evaluate the student's proposal to add black to both colours and white to the green. What will each addition actually do?
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Black lowers both chroma and value, but it does so by greying the mixture. It can make olive green look dirty and terracotta look muddy, and it reduces the hue difference between them. Black is not a reliable neutraliser because it is a pigment, not a true complement; it can also cool the mixture unpredictably. The student wants 'dull', but what is needed is 'muted' - lower saturation while keeping the hue readable. Burnt sienna or a touch of complementary colour does that better.
White raises value and usually cools the mixture. Added to green it produces mint or sage, not olive; it also reduces saturation and can make the border chalky. White is useful for the terracotta background if the value is too dark, but it should be used sparingly and after the hue is correct.
The correct order is: hue first, value second, saturation third. The student is trying to fix saturation with black and value with white before the hue is right. That is why the first try looks 'fresh' and unrelated.
3. Design a two-trial test that predicts the dried colour, and state the order in which you would paint the panel.
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Use two trials only, each on the same handmade paper, because the paper's absorbency changes the result.
Trial 1: mix the recipe above. Paint two adjacent swatches - one thin wash, one thicker layer - and dry them near the north window or with a hair dryer on cool. Label the ratios. Trial 2: change one variable only. For example, increase burnt sienna in the green by a pinch and increase white in the terracotta slightly. Dry and compare.
Judge the swatches at 2 metres, not at arm's length. Choose the pair with a clear value difference and a shared earthiness. Because colours dry lighter, the chosen wet mixture should look slightly darker and stronger than the target.
Painting order: lay the large terracotta background first, because it sets the value against which the border will be judged. Let it dry. Then paint the olive border, checking it against the dried background at 2 metres. If the border disappears, darken it with a touch more sienna and blue rather than adding black. Keep the leaf shapes simple so the border reads as a rhythm, not a texture.