ABSTRACT
This chapter aims to discuss scientists working in photodermatology with the basic concepts related to light measurement and light source characterization that are necessary for reproducible scientific tests. A photodermatologist will choose a specific ultraviolet (UV) source to match best a given biological action spectrum in order to achieve the greatest efficiency in delivering a photobiologically significant dose. Radiometric quantities such as radiant power must be used to describe and quantify ultraviolet radiation (UVR). Most simple instruments have a “broadband” spectral response that may cover just a band in the UV or may include the visible. In addition to the broadband instruments, it will be necessary to use a spectroradiometer to measure the spectrum of the incident UVR. When considering UVR bioeffects, it is useful to employ the convention of the International Commission on Illumination for spectral bands. Prior to using any UV meter or spectroradiometer, one should attempt to perform a general characterization of the instrument.
