Color of dried semen becomes yellow to brown. Dried semen stain in clothes is identified by:

When dried semen is examined under filtered ultraviolet light, they show a fluorescence of a bluish-white colour, which is not specific as other albuminous materials such as nasal, leucorrhoeal discharges and detergents also fluoresce. Fluorescence depends on choline of semen. Ref: The Essentials of Forensic Medicine and Toxicology, 27th edition, Page 369.