THE LASER DETECTION METHOD HAS WIDE APPLICABILITY BUT IS DEFICIENT IN A NUMBER OF CASES FOR THE FOLLOWING REASONS: THE SUBSTRATE LUMINESCES STRONGLY, OVERWHELMING THE USUALLY WEAK INHERENT FINGERPRINT LUMINESCENCE; THE SUBSTRATE DOES NOT ACCEPT THE FINGERPRINT SUFFICIENTLY WELL; AND FINGERPRINTS DEPOSITED BY A MINORITY OF INDIVIDUALS DO NOT SHOW SUFFICIENT INHERENT LUMINESCENCE. THE USE OF LUMINESCENT POWDER IS PARTICULARLY CONVENIENT IN THE ANALYSIS OF LATENT FINGERPRINTS. A NUMBER OF SUBSTRATES LUMINESCE STRONGLY ON ARGON-ION LASER ILLUMINATION. OFTEN, THIS LUMINESCENCE IS YELLOW-ORANGE. IF THE FLUORESCENT MATERIAL USED TO TREAT AN EXHIBIT LUMINESCES IN A SPECTRAL REGION IN WHICH LITTLE OR NO SUBSTRATE LUMINESCENCE OCCURS, THEN SUITABLE BANDPASS FILTERS CAN PERMIT LONG PHOTOGRAPHIC EXPOSURES TO REVEAL VERY FAINT FINGERPRINTS. NORMAL PHOTOGRAPHY DOES NOT HAVE THIS FEATURE BECAUSE LIGHT REACHING THE CAMERA IS SCATTERED FROM THE LATENT PRINT AND THE SUBSTRATE. EXPERIMENTS SHOW THAT MOST ARYLAZO-2-NAPHTHOL PIGMENTS CAN BE USED TO PREPARE DUSTING POWDERS WELL-SUITED TO THE LASER METHOD. A LATENT FINGERPRINT TECHNIQUE TREATMENT ANALOGOUS TO THE NINHYDRIN METHOD, INVOLVING PARADIMETHYLAMINOCINNAMALDEHYDE, HAS BEEN REPORTED. FLUORESCAMINE IS ALSO A WELL-KNOWN REAGENT FOR THE ASSAY OF AMINO ACIDS THAT HAS BEEN USED IN THE DETECTION OF LATENT FINGERPRINTS. FLUORESCAMINE-TREATED LATENT PRINTS ARE RENDERED VISIBLE BY ILLUMINZATION WITH AN ULTRAVIOLET LAMP. FINE DETECTABILITY USING THE FLUORESCAMINE TREATMENT TOGETHER WITH MODERATELY POWERFUL ARGON-ION LASERS EQUIPPED WITH THE ULTRAVIOLET OPTION CAN BE EXPECTED. CHROMATOGRAPHIC AND SPECTROSCOPIC STUDIES OF FINGERPRINT MATERIALS SUGGEST THE FEASIBILITY OF PHOTOCHEMICAL REACTIONS LEADING TO LUMINESCENT PRODUCTS BEING DETECTABLE WITH AN ARGON-ION LASER. PHOTOGRAPHS OF LATENT FINGERPRINTS AND REFERENCES ARE INCLUDED. (DEP)