Dried Semen stains on clothes identified by:
Spectrometry
UV rays
Infrared rays
LASER
B i.e. UV rays When examined under filtered ultraviolet (UV) light, seminal fluid (semen) show a fluorescence of bluish white colourQ, which is not specific as other albuminous materials such as nasal, leucorrhoeal discharges, detergents and stains of urine also fluoresce.