Our quick drying Ninhydrin Spray is supplied in an easy to use pump misting bottle and is an extremely sensitive method for developing old latent prints on paper documents, letters, newspaper, envelopes, wrapping paper, checks and even wallpaper at a crime scene. Ninhydrin reacts to the proteins and amino acids found in fingerprints. When ninhydrin is sprayed on the suspected area, the print will appear purple in color when heated to approximately 220 degrees in an oven or with a hair dryer or infrared lamp. We also offer Extra-Strength Ninhydrin Spray which has been specially formulated to eliminate ink from running on paper. A detailed instruction sheet is supplied with each ninhydrin spray bottle.