Lighting colour temperature

Correlated colour temperature in kelvin describes the warm or cool appearance of light, not its brightness. Keep it reasonably consistent within a room and choose it for the task and personal preference.

Practical example

A 20 m² room with a 150 lx target needs 3,000 lumens reaching the plane. With UF 0.65 and MF 0.80, the sources need about 5,769 lm. Six 1,000 lm fixtures give an estimated 156 lx.

Limitations

The simplified model does not know fixture intensity curves, individual surface reflectance, obstacles, glare or uniformity. A construction-ready design requires photometric data and suitable software.