What is colour temperature and what is CRI?
Colour temperature (in Kelvin) describes how warm or cool a light source looks; CRI (0–100) describes how accurately that light source renders colours compared with daylight — a light can be a flattering temperature but still render colours poorly if its CRI is low.
What’s affected
- undertone appears shifted (temperature)
- colour accuracy (CRI)
Colours that tend to cope better
Under a high-CRI bulb, most colours render close to how they look in daylight — CRI matters more for colour accuracy than for aesthetic preference.
Colours to watch
Cheap, low-CRI bulbs can make subtly different colours (two near-identical whites, for example) look either more or less alike than they really are.
Testing advice
Where colour accuracy really matters, look for a bulb's stated CRI (Ra) value — a higher number renders colour closer to daylight.
Lighting simulations and descriptions here are approximations, not exact physical predictions — see methodology.
Related terms
Sources
- CIE (International Commission on Illumination) publications — CIE