L4_CHEM480_JCCYu - Physical Developer (PD) A chemical...

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1 Physical Developer (PD) ± A chemical method for developing latent fingerprints on porous surface. ± For porous surfaces, it is better to do DFO first, then ninhydrin, then PD. Document each steps for fingerprints. ± The chemistry of PD will be discussed with a The chemistry of PD will be discussed with a demo.
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2 Chemistry of Physical Developer ± Most of the amine-containing compounds are water soluble, thus visualizing reagents are in a nonaqueous carrier. (i.e DFO, ninhydrin) ± PD is water based. It visualizes the water- insoluble portion of the fingerprint residues. Fats oil (lipids ± Fats, oil (lipids) ± Water-resistant proteins, lipoproteins ± PD process: selectively reduce silver onto fingerprint residues. Photographic Chemistry Chemical Developer: selectively reduces only the photo-exposed silver halide to metallic silver ± Photographic film: photosensitive silver halide crystals densely distributed in a gelatin matrix. AgX
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This note was uploaded on 04/02/2009 for the course CHM 480 taught by Professor Yu during the Spring '09 term at Sam Houston State University.

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L4_CHEM480_JCCYu - Physical Developer (PD) A chemical...

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