🎨 Colour theory and perspective

Complementary colours are pairs of colours that sit directly opposite each other on the colour wheel, like red and green, or blue and orange, and when placed side by side, each colour makes the other look more intense and vivid than it would appear alone. This effect happens partly because of how our eyes and brains process colour, since staring at one colour actually makes our eyes slightly more sensitive to its opposite, amplifying the contrast the moment the two sit next to each other. Artists use complementary colour pairs deliberately to create striking contrast and draw a viewer's eye toward a particular part of a painting, while mixing complementary colours together, rather than placing them side by side, actually produces a dull, muted brown or grey.

For a long time, painters showed distance mostly through size alone, making faraway things smaller without any consistent mathematical system, which often left paintings looking flat or a little strange to modern eyes. A breakthrough came when artists and mathematicians worked out linear perspective, a precise system built around vanishing points and horizon lines that let painters calculate exactly how much smaller and closer together distant objects should appear. Once this system spread among painters, it transformed how convincingly artists could depict entire cities, long hallways and vast landscapes, making flat paintings feel like windows into genuinely three dimensional spaces.

Every shadow in the real world falls in a direction and length determined entirely by where the light source sits, so a painting with shadows scattered in inconsistent directions instantly feels wrong to viewers, even if they cannot quite explain why. Artists carefully track a single consistent light source throughout an entire painting, working out exactly how long, dark and slanted every shadow should be based on that one imagined position of light. Getting shadows consistent is one of the fastest ways to make a flat painting feel convincingly three dimensional, since our brains rely heavily on shadow patterns to judge the shape, depth and position of objects in anything we look at.

A colour wheel arranges all the colours in a circle based on how they are mixed from a handful of basic colours, showing at a glance how every colour relates to its neighbours and its opposites around the circle. Artists use the colour wheel to plan out a painting's whole colour scheme before they even begin, choosing colours that sit close together for a calm, harmonious feeling, or colours that sit far apart for bold, energetic contrast. Understanding the colour wheel also helps an artist predict exactly what will happen when two colours are mixed together, without needing to test every single combination by trial and error first.