The disclosed light standard system provides flat field illumination through the use of an integrating light chamber which is in communication with a microprocessor. The light chamber has at least one high performance light source, such as LED's, recessed within the walls and positioned to prevent light from directly exiting the chamber. A photosensor monitors multiple parameters within the chamber and interacts with the microprocessor to control intensity, temperature and wavelengths. The lights standard operates in benchmark, ratio light, linearity and transient response modes with all parameters being programmable and storable within said microprocessor.