Light quality parameters

• Color rendering index
Ra = 91-100 – daylight-like color

• Chromatic temperature
Tc = 5500K – 6500K – cold light similar to noon

• Circadian activation index
Ac = 75 – 115 – effects on nervous system similar to daylight


Tcp - Correlated Colour Temperature
Also known as CCT, it represents the warm or cold tone (chromaticity) of white light. Defined as the temperature of the body emitting only thermal radiation most similar to the light of the givenlight source.


Ra - General Colour Rendering Index
Also known as CRI it represents the similarity between ideal and given light. Calculated 100 less as an average of colour shift of eight colour samples (R1, R2,…R8).

Ac - Circadian Activation Index
Represents the content of activating blue components in a given light, compared to D65 daylight under the same illuminance. This component of light is
responsible for stimulating the brain. Source: article Light an Biological Clock in Czech magazine Světlo (Light), 6/2010, pages 56–58, ISSN 1212-0812.