Latent Fingerprint Development on Thermal Paper Using Traditional Ninhydrin and 1,2‐indanedione |
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| Authors: | Chun‐Chieh Chen MS Yung‐Chien Yu MS Henry C Lee PhD Yun‐Seng Giang PhD Sheng‐Meng Wang PhD |
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| Institution: | 1. Forensic Science Section, Changhua County Police Bureau, Changhua City, Taiwan;2. Department of Forensic Science, Central Police University, Taoyuan, Taiwan;3. Forensic Science Center, Criminal Investigation Bureau, Taipei, Taiwan;4. Henry C. Lee Institute of Forensic Science, University of New Haven, West Haven, CT |
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| Abstract: | Thermal paper poses a significant challenge to latent print development as it tends to change color when traditional fingerprint development formulations are applied to it. In this study, the optimal components of ninhydrin, 1,2‐indanedione, 1,8‐diazafluoren‐9‐one (DFO), and 5‐methylthioninhydrin (5‐MTN) for yielding clear fingerprints on thermal paper were determined by systematically adjusting the relative amounts of the reagents, polar solvents, and the nonpolar diluent petroleum ether, followed by validation on text‐printed thermal paper. Specifically, 3.0% ethyl acetate as the polar solvent in petroleum ether was found to be the optimal combination; the optimal dilution ratios of ninhydrin, DFO, and 5‐MTN original solutions with petroleum ether were 1 to 2, 11, and 7, respectively. The optimal concentration of 1,2‐indanedione in petroleum ether was 0.125 g/L, with a string of 0.5% ethyl acetate in petroleum ether. |
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| Keywords: | forensic science fingerprint latent print thermal paper ninhydrin 1 2‐indanedione 1 8‐diazafluoren‐9‐one 5‐methylthioninhydrin |
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