Colour temperature & the Kelvin scale

LED colour temperature measures the colour of a light source.

It defines the amount of yellow, red and blue in a light, or how these hues differ from a true white colour, making it more ‘warm’ (yellow end of the light spectrum) or ‘cool’ (the white through to blue end of the spectrum.)

Color temperature is measured in degrees Kelvin, a scale which positions the light on the visible light spectrum.

For example, light at sunrise or sunset is more towards the yellow and red end of the spectrum – the lower Kelvin temperatures. At noon, the light is bright and white – true daylight. Higher colour temperatures may then appear to have a slight bluish tinge to them.

Domestic and hospitality industry lighting is often towards the yellow or warm end of the spectrum, while industrial lighting is more often towards the higher or cool end of the spectrum.

Examples of Color Temperature

The following table offers a broader example of the types of color temperature:

Color Temp Example of light source
1500K – 1800K Sunlight at sunrise or sunset
Eg Candle light
2000K – 2700K Often used as accent lighting and in domestic and hospitality industry.
Eg High pressure sodium light.
3000K – 3200K Used in domestic and retail applications.
Eg Incandescent or halogen light.
3700K For a “softer white” light.
Natural white light source.
4000K Used in general lighting, factories, carparks and warehouses.
Cool white fluorescent light.
5000K – 5500K For horticulture, aquariums, and where high color definition is important. Daylight lamps for industrial use.
5600K Nominal sunlight (mid day during mid summer)
6000K – 6500K A brilliant white/blue white light.
Eg Mercury vapour light; xenon; daylight fluorescent light.