If the work of lighting design was just left to services engineers to meet regulation-determined illuminance criteria per application, then interior and exterior architectural spaces would become soulless environments. Using qualitative measurements, architects and lighting designers can make sure the architectural intention and aesthetic character of a space is not compromised.
The science of measuring light, photometry, specifically applies to light in a space. Photometrics gauges how humans perceive light — its coverage area, where light cuts off and the intensity of light in relation to distance from the light source. In practical terms, photometrics shows whether a lighting plan meets the qualitative and quantitative lighting requirements for a project.