Colour mixing and wash control in a still-life study
A candidate is painting a still life in watercolour on 300 gsm cold-pressed paper. The setup contains a red apple, a green glass bottle, a yellow lemon and a blue cloth. The palette contains cadmium yellow, ultramarine blue, alizarin crimson, burnt sienna, phthalo blue and white. For the bottle, the candidate mixes cadmium yellow with ultramarine blue, then adds alizarin crimson to darken the green; the result is a flat grey-green. For the apple's shadow, the candidate mixes black with cadmium red, and the shadow looks chalky. To lighten the lemon, the candidate adds poster-colour white to the watercolour yellow; the area becomes opaque and loses its glow. A second wash is applied over damp paper, and the first layer lifts, leaving muddy blooms. The candidate asks why the colours look dead and how to control the medium.
1. Diagnose the green and apple-shadow mixtures using colour theory, and propose corrected mixes from the given palette.
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Cadmium yellow is a warm yellow, and ultramarine is a warm, violet-biased blue; their mix is already slightly muted. Adding alizarin crimson introduces red, which is complementary to green, so it neutralises the green toward grey. That is why the bottle looks dead. For a cleaner bottle green, mix phthalo blue (a cool, green-biased blue) with cadmium yellow, and darken by increasing phthalo blue rather than adding red. If the green becomes too bright, add only a trace of the complement on the brush, not a full mixture.
For the apple shadow, black plus red is a dead mixture; use alizarin crimson with a little ultramarine to make a cool violet-red, or burnt sienna plus ultramarine for a warmer shadow. Keep the shadow transparent and cooler than the lit red.
2. Explain why the watercolour lifted and bloomed. Give practical controls and compare the handling with poster colour.
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Watercolour lifting happens when a wet wash rewets a damp underlayer: the brush water lifts pigment and binder, and the pigment redistributes as a bloom. Avoid it by letting each layer dry completely, using a drier brush and less water for the next layer, and not scrubbing. If a bloom forms, blot once with a clean damp sponge and let it dry; do not keep working it.
Poster colour behaves differently: it is opaque, so it can be layered light over dark, and white can be used for tints. In watercolour, white is not needed for the lemon highlight; reserve the paper white and use a pale yellow wash. Poster white added to watercolour makes it opaque and chalky, which destroys the glow.
3. Propose a layering plan for the still life using the limited palette, including warm-cool decisions and where to reserve white.
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Work from light to dark and from large shapes to small accents. Reserve white paper for the lemon highlight and the bottle highlight. Lay a pale yellow wash on the lemon and a pale blue wash on the cloth; let them dry. Build the bottle with a phthalo blue plus cadmium yellow green, keeping the edges transparent. Paint the apple with cadmium red, adding alizarin crimson for the shadow side; keep the shadow cool with a violet mix.
Place cast shadows last, using a cool grey-violet mixed from ultramarine and a touch of burnt sienna, not black. Use white only if the medium is poster colour; for watercolour, preserve transparency and let the paper do the lightening.