Artificial lighting is often required to study toxicant impacts on biological systems in the laboratory. Since light can effect the responses of both the organism and the toxicant, care must be taken to ensure that the laboratory lighting mimics the light conditions in the relevant compartment of the natural environment with respect to both intensity and spectral output. Photoinduction of toxicant action and responses of plants to UV-B provide examples of the need to control lighting in environmental testing. It is possible to simulate sunlight with respect to the visible:UV-A:UV-B ratio using a variety of lamps. The types of lights that are useful for building such sources are fluorescent, metal discharge, incandescent and microwave lamps. The methods of quantification of light that best fit environmental research are radiometric and quantum methods. This paper focuses on the types of artificial light sources that are commonly used in the laboratory and the quantification of light.