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Fluorescent Small Particle Reagent (SPR)

NCJ Number
154213
Journal
Journal of Forensic Identification Volume: 45 Issue: 2 Dated: (March/April 1995) Pages: 164-168
Author(s)
E Springer; P Bergman
Date Published
1995
Length
5 pages
Annotation
This paper describes a simple technique in which the standard small particle reagent (SPR) formulation can be made fluorescent so that developed latent fingerprints can easily be seen on both dark and multicolored surfaces.
Abstract
This technique enables the use of one formulation instead of different ones for each colored surface encountered. Two methods were examined for preparing a fluorescent SPR. Results revealed that the addition of a fluorescing agent, Brilliant Yellow 40 (BY-40), to the SPR suspension improves the contrast of developed prints on dark or multicolored backgrounds under excitation in the blue range of the spectrum. BY-40 was mixed with the SPR stock solution and was then diluted to a working suspension. One hundred ml of a 0.1 percent solution of BY-40 in ethanol was mixed with 100 ml of SPR stock suspension. SPR stock and working suspensions were prepared according to the procedure suggested by the Manual of Fingerprint Detection Techniques. Prints were placed on glass slides, multicolored glossy paper, a multicolored cola can, and black polythene. All items were then dipped in water. The samples were then sprayed with the BY-40 SPR suspension or another suspension. The prints developed were examined in white light and with a Rofin Polilight 300-watt light source. Excitation was made at 450 nm, 505 nm, and 530 nm, with observation above 549 nm. Photographs and 5 references