Abstract: In accordance with the present invention, a low noise light source for illuminating a treated or untreated deposition of material for forensic examination is disclosed. A light having a wide range of wavelengths is generated. The light is directed toward a reflective diffraction grating. The relative position between an exit slit and the grating is repeatedly adjusted to result in passage through the exit slit of different desired bands of wavelengths of output light from portions of the light reflected by the grating. The output light is directed through a filter, toward the deposition to be examined. The filter has a pass characteristic which substantially passes the desired bands and blocks the light that has a wavelength in an expected range of fluorescence of the deposition.

Abstract: A method of illuminating a deposition of organic material such as, blood, sweat or oil for forensic examination is disclosed. Light having a wide range of wavelengths is generated and directed towards a reflective diffraction grating. The relative position of an exit slit with respect to the grating is adjusted to pass a desired band of wavelengths of output light from portions of the light reflected by the grating. The output light is then directed toward the deposition to be examined through the use of a fiber optic bundle, preferably a liquid fiber optic member. Adjustment of the relative position of the exit slit with respect to the grating is achieved by rotation of the grating. Movement is controlled by an electronic control and a handheld remote control pad.