Lighting Colour Temperature
In technical specifications for lighting and light fittings you will often see the term 'colour temperature' - but what is this? and what is the correct colour temperature you need for different commercial & industrial application?
Colour temperature - the ranges
Lighting colour temperature is measured in Kelvin (K) - artificial light is typically found in the range between 2700K and 6500K - with the light appearing cooler/bluer as the measured 'K' level is increased
The colour temperature is a measure of the colour appearance of a light source ranging from 'warm' light (e.g. - low and high pressure sodium lamps) through to 'cool' light (from metal halide lamps).
The effect of lighting colour on humans
The ranges of light colour have different effects on sleep cycle, productivity, and mood. Warm Light is relaxing which helps people to calm down and prepare for sleep. Cool White and Daylight contain blue spectra which helps people be wakeful, productive, attentive, and improves moods.
Circadian lighting
The natural colour temperatures observed over the course of a day produced by the sun vary from warm to cool. The early and late sunlight is low on the colour temperatures scale emitting a warm orange glow (2000K). The sunlight at midday is a cool blue colour temperature (10000K).
The right colour temperature of light for a workplace
Choosing a lamp with the right colour qualities is important in environments - particularly in large industrial buildings such as a factory or warehouse where lighting levels are crucial for maintaining good health and safety practices and keeping staff at maximum efficiency.
Here are some examples of appropriate colour temperatures for environments - a brief discussion follows:
| Environment | Typical Colour | Effect |
|---|---|---|
| Home, Living Room, Hotel, Restaurants | 2700K-3500K | Warm glow, relaxation, cosy atmosphere |
| Offices, Shops, Retail | 3500-4500K | Balanced White |
| Factory, Workshop, Warehouse | 4500K-6000K | Bright White - Precise, Vibrant, Crisp |
| Specialist environments | over 6000K | Cool White, Blue-tinged |
2700K-3500K - Warm Light
This light colour range gives a distinct warm glow that reminiscent of the sunset or a flame - it is more used at home and in relaxed commercial settings
3500K-4500K - Neutral White Light
This light colour range allows people to focus and remain alert for several hours when working in one space but still allows a degree of comfort
4500K-6000K - Bright White Light
This colour range is suitable in a workplace when clarity & precision is required - e.g. - specific working practices such as glass and metal works in a factory setting or environments such as healthcare
Over 6000K - Cool White
This light colour range can be common with some types of LED lighting which emit a more blue light to obtain a higher efficiency. It can be quite harsh to work under this colour light for many hours.
Reference diagram - Colour temperatures
The diagram illustrates this in more detail:
