SHEDDING LIGHT ON LIGHT AND LIGHTING

摘要

Photometry is the measurement of light and should be based upon a single luminous efficiency function that spans the entire range of human sensitivity to the electromagnetic spectrum. Multiple luminous efficiency functions lead to confusion and the photopic luminous efficiency function is too narrow to represent the spectral sensitivity of the human eye. Lighting is the application of light for the benefit of society, including safety, security, productivity, health and wellbeing. Just as different levels of illumination are recommended to provide those social benefits, the spectral composition of the sources providing those levels of illumination should be different. A family of benefit efficiency functions, each characterizing the spectral sensitivity of a different visual or non-visual channel, should be used to select those light sources. The family of benefit efficiency functions used for lighting should be conceptually distinct from the single universal luminous efficiency function underlying the definition of light.