What is colour temperature in Kelvin?

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.

Why does my shadow colour depend on the light temperature?

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.

How does paint medium affect colour temperature rendering?

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.

What is the complementary colour temperature?

The complementary colour temperature is the opposite point on the warm-cool spectrum. 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 principle is used extensively in Impressionist painting.

What does white balance equivalent mean for painters?

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.

ArtCalcs

Colour Temperature Calculator — Warm & Cool Bias for Painters

Calculate the warm/cool bias of your light source and get recommended palette adjustments, complementary temperature and white balance equivalent.

Colour Temperature

Kelvin value of your light source

Light Source TypeChoose your lighting situation

Paint MediumYour primary painting medium

SubjectType of subject being painted

How We Calculate This

Enter the colour temperature of your light source in Kelvin. If unsure, select the light source type and use its typical mid-range value.

How the calculation works

The calculator maps your Kelvin value to a warm/cool bias band:

Below 2800 K — Very Warm (candle/flame)
2800–3500 K — Warm (tungsten/incandescent)
3500–4500 K — Slightly Warm (warm fluorescent)
4500–5500 K — Neutral (studio/cloudy)
5500–7000 K — Cool (daylight/overcast)
Above 7000 K — Very Cool (deep shade/blue sky)

Complementary temperature is calculated as approximately 12,000 minus the input Kelvin, clamped to the 2000–10,000 K range. The advanced options allow fine-tuning of the warm/cool bias offset and shadow/highlight intensity factors used in the subject recommendations.

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Always verify quantities before purchasing materials.