The understanding of colour dates back to antiquity. Aristotle, in his treatise "De Sensu et Sensibilibus" (c. 350 BC), proposed that all colours derived from mixtures of white and black — a theory that dominated for nearly two millennia. The Egyptians already mastered six fundamental pigments, including Egyptian blue, the first synthetic pigment in history, created around 3100 BC from copper and calcium silicate. It was Isaac Newton who revolutionised this understanding in 1666, decomposing white light through a glass prism in his room at Trinity College, Cambridge. He identified seven colours — red, orange, yellow, green, blue, indigo, violet — a deliberate choice to create a parallel with the seven notes of the musical scale. His findings, published in "Opticks" in 1704, established that colour is an intrinsic property of light, not of objects.
Colour theory flourished in the 18th and 19th centuries. Johann Wolfgang von Goethe, in his "Theory of Colours" ("Zur Farbenlehre") published in 1810, opposed Newton by emphasising the subjective experience of colour. Although his physics was flawed, his observations on simultaneous contrasts and complementary colours profoundly influenced the visual arts. Michel-Eugène Chevreul, a French chemist and director of dyeing at the Gobelins Manufactory, published in 1839 "On the Law of Simultaneous Contrast of Colours", a work demonstrating how adjacent colours mutually alter their perception. His research directly impacted the Impressionists — Monet, Pissarro — and especially Georges Seurat's pointillism, whose "A Sunday Afternoon on the Island of La Grande Jatte" (1886) literally applies Chevreul's principles.
The modern understanding of colour rests on the trichromatic theory of Thomas Young (1802), refined by Hermann von Helmholtz in the 1850s. They demonstrated that the human eye perceives colours through three types of retinal cones sensitive to red, green and blue respectively. James Clerk Maxwell proved this theory in 1861 by producing the first colour photograph in history: a Scottish tartan ribbon, photographed through three red, green and blue filters, then superimposed by projection. The RGB (Red, Green, Blue) model of additive synthesis, used by all modern screens, stems directly from this work. Subtractive synthesis (CMYK — Cyan, Magenta, Yellow, Key/Black), meanwhile, was formalised for industrial printing in the early 20th century.
The need to standardise colours spawned several major systems. Albert Munsell, an American painter and teacher, created the first systematic colour space in 1905, organising colours along three axes: hue, value and chroma. In 1931, the International Commission on Illumination (CIE) published the CIE XYZ colour space, the first mathematical model capable of describing all perceivable colours. Pantone revolutionised the graphic industry in 1963 with its Pantone Matching System (PMS), a colour guide now containing over 2,100 referenced shades. With the advent of the web, hexadecimal codes (#RRGGBB) were adopted from HTML 2.0 in 1995. The 216 "web-safe colors" were defined to guarantee identical rendering on the 8-bit screens of the era. The HSL (Hue, Saturation, Lightness) format was introduced in CSS3 in 2011 to offer designers a more intuitive model.
Colour psychology has been an active field of research since the pioneering work of Faber Birren in the 1940s. In "Color Psychology and Color Therapy" (1950), he documented the influence of colours on emotions and behaviour. Neuromarketing studies show that website visitors form their first impression in under 50 milliseconds, and that the dominant colour influences up to 90% of this initial evaluation (Satyendra Singh's 2006 study, "Impact of Color on Marketing"). Blue inspires trust — hence its omnipresence at Facebook, LinkedIn, PayPal and IBM. Red creates urgency and stimulates appetite (Coca-Cola, McDonald's, Netflix). Green evokes nature and health (Spotify, WhatsApp, Starbucks). However, these associations vary considerably across cultures: in China, red symbolises prosperity; in Japan, white is the colour of mourning; in India, saffron represents the sacred.
Today, random colour generators are essential tools for designers and developers. The WCAG 2.1 standard (Web Content Accessibility Guidelines) requires a minimum contrast ratio of 4.5:1 between text and its background to ensure readability. The generative art movement, popularised by artists such as Casey Reas (co-creator of Processing in 2001) and Tyler Hobbs (creator of Fidenza, 2021), uses random algorithms to produce digital artworks where colour plays a central role. Modern design systems — Google's Material Design, Apple's Human Interface Guidelines — all incorporate rigorously calculated palettes with CSS variables for light and dark themes. The Pantone Color of the Year, awarded since 2000, influences the global design industry: in 2023, "Viva Magenta" generated over 30 billion media impressions within two weeks of its announcement.