The colour wheel and harmonies

The colour wheel is a disc that arranges the twelve main colours according to their position in the spectrum. Red, yellow and blue are the three primaries, spaced 120° apart. Between them, the secondary colours (orange, green, violet), then the tertiaries. This wheel is not decorative, it is a decision-making tool.

Four relationships between colours always work. Monochromatic (a single hue in multiple values). Complementary (two colours opposite on the wheel). Analogous (three neighbouring colours). Triadic (three colours at 120°). Everything else is a variation of these four families.

The trap is believing you can "feel" a harmony without knowing the wheel. You can, sometimes. But when it goes wrong, it goes badly wrong, and you do not know why.

Choose the atmosphere you are after first, then the corresponding harmony.

For a calm and deep interior, go with a monochromatic scheme. A single colour, expressed in three or four values. Light beige on walls, medium beige on the sofa, rich beige on cushions, chocolate brown on an armchair. It is the safest harmony, almost impossible to get wrong. It is also the most monotonous if you do not introduce variations in texture.

For an elegant and structured contrast, choose complementaries. Blue and orange, green and red, yellow and violet. One of the two must be heavily dominant, the other serves only as an accent (see rule 01.1). Deep teal on a large wall, terracotta touches on cushions and artwork. Not the other way around.

For an enveloping and natural feel, choose analogous colours. Three neighbouring colours on the wheel, for example green, blue-green, blue. This logic is found in landscapes, which is why it calms the eye.

For a lively and graphic room, try a triadic scheme. Three equidistant colours, but one dominant, the other two as touches. Blue, yellow, red in Mondrian-inspired interiors, or blue, green, orange in a Mediterranean kitchen.

India Mahdavi is arguably the most virtuosic practitioner of deliberate complementary harmonies. Her Sketch restaurant in London works a dominant powder pink against a deep green velvet, with a few gold touches. Technically a graduated triad, but the eye reads the pink/green tension first.

Jean-Louis Deniot practises sophisticated monochromatic schemes in his Parisian salons. Seven or eight values of beige, from near-white cream to deep taupe, across walls, curtains, rugs and furniture. The eye perceives a single "colour", but the richness comes from the subtle variations.

For triadic harmonies, Studio KO excels in their Moroccan projects, playing majorelle blue, deep ochre and palm grove green. The rule they hold: never equal, always one clear dominant at 60%.