THE USE OF HYDROGEN FLUORIDE IN THE DEVELOPMENT OF LATENT FINGERPRINTS FOUND ON GLASS SURFACES.

This article discusses the use of hydrogen fluoride in the development of latent fingerprints found on glass surfaces. The use of hydrofluoric acid for the development of latent fingerprints on glass surfaces bas been suggested by several investigators. In each instance, however, the use of hydrofluoric acid, an aqueous solution of the gas hydrogen fluoride, is suggested rather than the use of hydrogen fluoride itself. This investigation was conducted using hydrofluoric acid vapor, a mixture of hydrogen fluoride and water vapor, rather than liquid hydrofluoric acid. The choice of the acid vapor is based upon the well established fact that the destruction of fingerprint detail is greatly increased with an increase in the density of the developing medium. For example, a gas or vapor technique such as iodine or osmium tetroxide fuming should he one of the first methods considered for the development of latent fingerprints (1) (2) (3) (4) (5). The reactions between hydrofluoric acid and silicates are well understood.