Colour temperature is a characteristic of visible light that has significant implications in the lighting industry, it is also a considerable factor in photography, publishing, manufacture and horticulture, to name just a few.
The temperature of a colour indicates the spectrum at which it radiates, otherwise referred to as “hue”. The temperatures and their corresponding hue are based upon the light emitted by an “ideal black body radiator”. It is referred to as ideal because black absorbs all external electromagnetic radiation, reflecting no light of any kind. As this black radiator is heated it will begin to glow and emit light, starting with a dull red glow. As the heat intensifies it becomes orange, yellow then white, until eventually emitting light in a colder blue spectrum.
The temperature of the radiator is quantified in Kelvin (K). Contrary to cultural association, lower temperatures have warmer light characteristics and higher temperatures have cooler light characteristics. The figure below indicates at which temperatures certain hues of colour are radiated.
With regard to the lighting industry, there is no one colour temperature that suits all environments and applications. Consideration as to what a space or environment is used for is often the deciding factor when choosing a colour temperature as it is also proven to have an effect on the behaviour and mood of individuals.
For example, a warmer colour temperature (2700K-3000K) is generally considered to be more welcoming and often used in restaurants and receptions. It also complements skin tones, bathrooms lend themselves to warmer colour temperatures. Whereas cooler colour temperatures (5000K-6500K) closely replicate natural sunlight and are often used to encourage concentration in offices or in areas where close examinations are conducted, such as galleries and jewellery shops.
The table below details a number of typical environments where different colour temperatures might be used.