LED lighting is characterised by its ability to produce nearly any colour of light in the visible spectrum, something that is not possible with conventional lamps.
However, this also means extra care must be taken to select a product that matches the intended application.
White is the lighting colour most widely used by human society, but not all types of white light are the same. For example, incandescent and sodium vapor lamps provide a warm and yellowish output, while metal halide bulbs offer a neutral tone. The specific hue of white light has a significant impact on how an environment is perceived by humans, and this must be considered during lighting design.
The correlated colour temperature (CCT) is a metric used to describe the output of a lamp, where lower CCT values indicate warm tones and higher values indicate cool light; an incandescent bulb with a CCT of 2700K has a yellow tinge, while a fluorescent tube with a CCT of 6500K will seem slightly blue.
Warm White Lighting
LED fixtures with CCT values of 3000K or less provide a warm white output, creating a relaxing environment. Therefore, they are commonly used in restaurants, hotels, bedrooms or other similar locations not intended for work activities. Warm white lighting is not recommended in commercial and industrial settings, since its relaxing effect can be detrimental for productivity.
Cool White Lighting
Lamps and fixtures with a CCT of 5000K or above are on the opposite side of the white lighting spectrum, producing a cool and slightly blue output. Just like warm light has a relaxing effect, cool light enhances awareness and attention to fine details. LED lighting with these characteristics is preferred in applications such as the following:
- Industrial spaces where precision work is carried out
- Outdoor lighting in commercial and industrial locations
- Some retail applications such as jewellery
Cool white light is not recommended for households, especially in bedrooms, where it can cause sleep problems for occupants.
Neutral White Lighting
Lighting products with a CCT of around 4000K produce a neutral output, which is neither warm nor cool, offering a balance between awareness and relaxation. Lighting of this type is preferred in locations where people will carry out tasks requiring concentration for long periods of time, such as classrooms, offices and kitchens. Cool white light can become stressing after long-term exposure, so neutral white is used in these cases.
The colour of lighting is a very important aspect to consider for any installation, and especially when older lamps or fixtures are being upgraded to LED. Ideally, a lighting system should offer energy efficiency, while creating an indoor environment that suits the activities that will be carried out.