FSC239Y5 Lecture Notes - Lecture 8: Zinc Chloride, Ninhydrin, Usability
Document Summary
They are persistent, meaning that they never change. There is a limited variability in terms of classification and individualization via the fingerprint database. They form in the womb, never changing after birth. Conclusions that can be drawn based on fingerprints include identifications, exclusions, and inconclusivity (meaning that more evidence is needed). Two fingerprints are never the exact same because partials can be formed, and variability is present. They can never be (cid:873)identical,(cid:874) only from the same source. Substrates, impression depth, positioning, and other factors influence specific details. Types of impressions include latent, visible/patent, or plastic/mold impressions. Choosing a technique involves preventing destruction, the surface (porous or nonporous) that the fingerprint is on, or the substance the print is located in. Methods include dfo, ninhydrin, indanedione/zinc chloride, 3d casting, iodine, and/or camphor. Fibreglass filament brushes are used to dust the chosen granular (or magnetic (using iron filings) powder with a different magnetic tip) and develop the print.
