Yellow & Indigo

Yellow and indigo creates the Toulouse-Lautrec Moulin Rouge combination — because Henri de Toulouse-Lautrec (1864–1901, the most celebrated Post-Impressionist printmaker and the creator of the modern advertising poster) produced a series of lithograph posters for the Moulin Rouge cabaret (Boulevard de Clichy, Paris, 18th arrondissement, Montmartre, opened 1889) that consistently use the combination of vivid yellow (the yellow of the cancan dancers' skirts, the yellow of the gas-lit stage, and the vivid yellow of the poster's most attention-catching graphic elements) and deep indigo-blue (the dark night sky of Montmartre, the deep indigo of the Moulin Rouge's night audience, and the deep cool of the most dramatically night-lit cabaret environment). Toulouse-Lautrec's 'Moulin Rouge: La Goulue' (1891, the first mass-printed modern advertising poster, lithograph, 191 × 117cm, now in the Musée d'Orsay and the MOMA) uses the vivid yellow and dark indigo-blue as the most graphic warm-cool in the most celebrated early advertising poster.

Japanese aizome (藍染, natural indigo dyeing) tradition — the most ancient and the most culturally significant Japanese textile colouring tradition, using Polygonum tinctorium (Japanese indigo, ai-kusa) cultivated in Tokushima Prefecture and other regions to produce the characteristic deep indigo of Japanese kimono, noragi workwear, and shibori tie-dye textiles — creates a yellow-and-indigo warm-cool when the deep aizome indigo is combined with the most specifically Japanese yellow of the yuzu citrus, the Kyoto shichimi togarashi, or the gold of the Japanese autumn maple (koyo).

Newton's Opticks (1704) and the visible spectrum — Isaac Newton's description of the seven colours of the visible spectrum (red, orange, yellow, green, blue, indigo, violet — the mnemonic Roy G. Biv) identified indigo as a specific colour band in the visible spectrum (approximately 420–450nm, between blue at 450–495nm and violet at 380–420nm), making yellow and indigo spectrally non-adjacent but visually highly contrasted. Newton's specific choice to name indigo as a distinct spectral colour has been debated — he chose seven spectral colours to match the seven notes of the musical scale — but indigo's designation as a specific spectral colour gives yellow-and-indigo a unique Newton-Opticks scientific authority in the spectrum tradition.