The colour rendering determines whether the light makes colours appear dull or bright. It is divided into categories such as 1A, 1B, 2A, 2B and so on. Category 1A represents the best possible colour rendering. light11 generally recommends 1A colour rendering for the home, while the bathroom represents an exception in this context. Here fluorescent lamps and compact fluorescent lamps are recommended as they provide extensive lighting with few shadows and thereby ensure the optimal illumination for faces. These lamps usually work best with a colour rendering of 1B.
Colour rendering can also be measured using the more precise general colour rendering index (Ra
). This also describes how accurately colours are rendered in artificial light. Ra
=100 is the best colour rendering possible – the lower the value, the less favourable the colour rendering of a lamp.
Colour rendering index Ra
Colour rendering quality
90 - 100
12 V and 230 V eco halogen lamps, 12 V and 230 V halogen lamps, incandescent lamps
80 - 89
Compact fluorescent lamps, fluorescent lamps, energy-saving lamps with electrical ballast, discharge lamps
60 - 79
Fluorescent lamps, high-pressure mercury vapour lamps
40 - 59
High-pressure mercury vapour lamps
0 - 39
High-pressure and low-pressure sodium vapour lamps