Fingerprint Sciences: History, Techniques, and Classification

This second easy-level Fingerprint Sciences mock covers a completely fresh set of topics — no repetition from the first easy mock — spanning fingerprint history, development chemistry, the Henry classification system, the ACE-V methodology, post-mortem techniques, and the anatomy of friction ridge skin. All thirty questions are pitched at the definitional level with focused, specific options.

Questions cover why Bertillonage failed (the Will West scaling problem), ridge counting in the Henry system (delta to core line), the three whorl tracing results (Inner/Meeting/Outer), the Francisca Rojas case 1892 (first criminal fingerprint case, Vucetich, Argentina), the Mayfield case 2004 (cognitive bias leading to false identification by three FBI examiners), type lines definition (two innermost diverging ridges), fluorescent powder applications (multicoloured surfaces), Rhodamine 6G and Basic Yellow 40 as post-cyanoacrylate dye stains, friction ridge skin formation timing (16–24 weeks gestation), the core definition (innermost recurving ridge in a loop), magnetic powder technique (magnetic wand, bristle-free), why identical twins have different fingerprints (random environmental factors in utero), ALS mechanism (fluorescence excitation and barrier filter), crystal violet for adhesive surfaces, ACE-V inconclusive outcome definition, fingerprint powder physical adhesion mechanism (sebaceous oils), People v. Jennings 1910 (first US fingerprint conviction), sebaceous gland secondary transfer to volar skin, IAFIS and CODIS both return candidate lists requiring human confirmation, post-mortem skin slippage technique (slip over examiner's gloved finger), fingerprint forgery detection artefacts (reversed image, no pressure distortion), inherent fluorescence of sebaceous oils and food residues, Level 1 detail definition (gross pattern features), rolled vs plain impression recording difference, the Mayfield blind verification lesson, development sequence principle (non-destructive to destructive), fingerprint evidence as physical evidence, aluminium powder on dark surfaces (silver-white contrast), Henry secondary classification by right index finger, and the etymology of friction ridge.

Themes covered:

• History: Bertillon failure, Rojas 1892, Jennings 1910, Mayfield 2004
• Henry Classification: ridge counting, whorl tracing (I/M/O), secondary classification (right index finger)
• Development techniques: fluorescent powders, Rhodamine 6G/Basic Yellow 40, crystal violet (adhesive), magnetic powder, inherent fluorescence, development sequence
• ACE-V: inconclusive outcome, blind verification lesson (Mayfield)
• Anatomy: type lines, core, sebaceous gland transfer, friction ridge formation timing, twins
• ALS: mechanism, applications
• Operational: rolled vs plain impressions, post-mortem skin slippage, fingerprint forgery detection, IAFIS vs CODIS, fingerprint as physical evidence

Each question carries a detailed explanation citing Ashbaugh's Quantitative-Qualitative Friction Ridge Analysis, Lee and Gaensslen's Advances in Fingerprint Technology, and the PCAST 2016 report. Allow 15 minutes.