ABSTRACT
The use of powders is one of the oldest reported techniques for development of latent €ngerprints. Faulds, in his publication Dactyloscopy in 1912 [1], refers to the experiments conducted by Forgeot in the late nineteenth century as the €rst studies into the powdering technique, and also comments on subsequent experiments of his own [2]. By 1912 Faulds [1] was able to describe formulations and application techniques for both black and white powders, and by 1920 many more types of powders had been reported for development
CONTENTS
8.1 History of the Technique .................................................................................................. 191 8.2 Theory.................................................................................................................................. 194 8.3 Applications of the Technique ......................................................................................... 195 8.4 Equipment ........................................................................................................................... 195
8.4.1 Powders ................................................................................................................... 195 8.4.1.1 Flake Powders .......................................................................................... 196 8.4.1.2 Granular Powders ................................................................................... 198 8.4.1.3 Magnetic Powders ...................................................................................200 8.4.1.4 Fluorescent Powders ............................................................................... 202 8.4.1.5 Miscellaneous Powders .......................................................................... 203
8.4.2 Brushes .................................................................................................................... 204 8.4.2.1 Glass Fiber Brushes ................................................................................. 206 8.4.2.2 Polyester Fiber Brushes .......................................................................... 206 8.4.2.3 Animal Hair Brushes .............................................................................. 207 8.4.2.4 Feather Brushes ....................................................................................... 208 8.4.2.5 Magnetic Applicators ............................................................................. 209
8.4.3 Lifting Materials .................................................................................................... 209 8.4.3.1 Adhesive Tapes and Sheets .................................................................... 211 8.4.3.2 Gelatine Lifts ........................................................................................... 211 8.4.3.3 Casting Compounds ............................................................................... 211
8.5 Imaging of Powdered Marks ............................................................................................ 211 8.6 Powder Selection ................................................................................................................ 213 8.7 Nanoparticles ..................................................................................................................... 215 Acknowledgments ...................................................................................................................... 215 Authors ......................................................................................................................................... 215 References ..................................................................................................................................... 216
of €ngerprints, including mercury-chalk (hydrargyrum-cum-creta), graphite, lamp black, ferric oxide, magnesium carbonate, aniline dye stuffs, lycopodium powder-Sudan red mixture, red lead oxide, lead carbonate, lead iodide, and lead acetate [3]. By the end of the decade, a further selection of €ngerprint development powders had been reported, including the €rst references to the use of aluminum powder. The purpose of many of these materials was to provide investigators with a range of different colored powders that could be used to both develop a crime scene mark and provide contrast with colored backgrounds. Some of these early powders persisted in use for many years. Mercury-chalk was still in use in the United Kingdom in the 1970s, and carbon black-based powders remain in use worldwide to the current day.
