Compared to indirect lighting with diffuse light, the direct aimed light results in better modelling capability. Combined lighting with direct and indirect components ensures good visual comfort both in the room and on the work surface.

Lighting criteria for usable areas:
- illuminance level dependent on activity
- luminance distribution to avoid direct and secondary glare
- cut-off angle and position of the luminaire restrict glare and increase visual comfort
- the choice of lamp determines the light colour and colour rendition