What is Kelvin? Understanding Colour Temperatures

Shopping around for a new LED light or flash and wondering what those numbers mean that keep cropping up, and what 'colour temperatures' are? Look no further. We've got all the information you need and more on Kelvin and Colour Temperatures to help you pick your new lighting equipment.

Kelvin is a measurement commonly used for heat temperature, and also the measurement for colour temperature for light. This falls under "Correlate Colour Temperature", also known as CCT, which is compared to Kelvin in temperature. This rating can be found on just about any photography or video light you'll pick up, but you can also find it on household bulbs too, to help you pick the right colour bulb for your light or lamp.

CCT and Kelvin are quite easy to understand once you know how. 

The higher the number, the whiter the light, with the highest ratings being more blue.

Lower Kelvin ratings equal more orange toned light, a bit like a sunset. 

Adjustable Colour Temperature

The Daylight Balanced 5600K measurement corresponds the closest to the natural colour of daylight aka sunshine. This makes it the most natural-looking light colour, and will seem the most "normal" to most viewers.

Most flashes for photography will be set at around 5600K, with the intention of matching sunlight as closely as possible. LEDs, on the other hand, can come in Daylight Balanced or Bi-Colour options, which allow you to adjust the colour temperature of your light freely for things like creative film projects or to colour-correct on-location shoots.

Bi-Colour lights have an adjustable colour temperature, generally with a range of between 3200-6500K, unless you're looking for a more professional, powerful light which may have a wider range. 

Some professional lights can even have CCT adjustable up to 10,000K, like the brand new MG6K COB LED from Godox KNOWLED! This is designed for high-end, large-scale professional video productions. 

Need help picking an LED light in general? Check out our upcoming blog: Choosing LED Lighting

Daylight Balanced vs Bi-Colour Temperatures

LC30D (left) with a 5600K temperature. LC30Bi (right) set to a lower temperature of about 3200K.

Does Colour Temperature Impact my Image?

Disclaimer: If you're looking at shooting something like portraits, the best colour temperature you can stick with is 5600K, aka daylight for the most natural effect. If you're shooting a more creative project or film for example, then that's when colour temperature may come into play.

Kelvin colour temperature choices will have an impact on how people perceive your images or video, due to the simple existence of basic Colour Theory. Part of this includes Colour Symbolism: i.e. that different colours can carry different meanings and emotions, especially depending on context.

For example, green is associated with nature as it's the colour of grass and leaves, while also being associated with luck. 

Yellow and orange (warmer colour temperatures) can be associated with:

Happiness, the sun/sunsets, danger/caution, fire, fruit, Halloween and more. Casting your scene in yellow or orange, depending on the context, will likely have a further impact on the message you're looking to purvey. 

Blue is often associated with the sea/water, the sky, sadness, coldness/ice, and royalty. 

The more blue and cold the cast of light on your scene, the more the viewer might think what they're viewing is colder, less approachable, or even sad. 

Do I need Bi-Colour lights or Daylight Balanced?

Bi-Colour lights are generally only needed for those situations where you have to balance other lighting, or if you need it for creative purposes. If you're shooting things like headshots or product photography, daylight balanced lights are your best option, and will save you a little bit of money too, as they generally cost a little less. 

If you're looking for even more colour flexibility, go with RGB instead! Then, you can access a whole array of colours and hues.