Colour Temperature Calculator — Warm & Cool Bias for Painters

Colour temperature is measured in Kelvin (K) and describes the warmth or coolness of a light source. Candles sit around 1500–1800 K (very warm orange), tungsten bulbs at 2700–3200 K (warm yellow), daylight at 5500–6500 K (neutral to cool), and shade at 7000–9000 K (distinctly blue). Higher Kelvin = cooler (bluer) light; lower Kelvin = warmer (more orange) light.

Shadows are influenced by their surrounding environment. In warm tungsten light, shadows often pick up cool ambient (daylight, sky) tones. In cool daylight, shadows may hold warm reflected ground or wall colours. Understanding the Kelvin temperature helps you choose the complementary shadow colour to create convincing depth.

Oil paint yellows over time due to linseed oil oxidation, shifting cool mixes warmer. Acrylics dry darker and slightly cooler. Watercolour allows luminous warm-over-cool layering. Gouache requires planning as it is opaque. The calculator provides medium-specific notes for each choice.

The complementary colour temperature shown here is an illustrative teaching aid rather than a measured standard — it simply reflects your input about the warm–cool midpoint to suggest a contrasting light note. Pairing complementary temperatures in your painting — for example, a warm-lit subject against a cool background — creates visual vibration, luminosity and a sense of atmospheric depth. This warm-light/cool-shadow contrast is used extensively in Impressionist painting, but use the figure as a compositional starting point, not a value to match on a colour meter.

White balance is a photography concept that describes how a camera would correct for a given light source. Understanding your scene's white balance equivalent helps you recognise what a photograph reference would look like versus what your eye perceives — useful when painting from photo reference under different lighting conditions.