Photometry is the science of measuring visible light. A photometric study of a luminaire would generally describe the fixtures’ spectral distribution, the direction of the light, the brightness of the luminaire and its visible spectrum.

Perceptual psychology is the field of science concerning the way visual stimuli are processed in the human brain.

Tip from a lighting designer

We design our lighting concepts always keeping in mind principles of perceptual psychology as everything we perceive is light.