Editing Fingerprint (section)

== Forensic laboratories ==
Although there are hundreds of reported techniques for fingerprint detection, many of these are only of academic interest and there are only around 20 really effective methods which are currently in use in the more advanced fingerprint laboratories around the world.

Some of these techniques, such as [[ninhydrin]], [[1,8-Diazafluoren-9-one|diazafluorenone]] and [[Evaporation (deposition)|vacuum metal deposition]], show great sensitivity and are used operationally. Some fingerprint reagents are specific, for example ninhydrin or diazafluorenone reacting with amino acids. Others such as [[ethyl cyanoacrylate]] polymerisation, work apparently by water-based catalysis and polymer growth. Vacuum metal deposition using gold and zinc has been shown to be non-specific, but can detect fat layers as thin as one molecule.

More mundane methods, such as the application of fine powders, work by adhesion to sebaceous deposits and possibly aqueous deposits in the case of fresh fingerprints. The aqueous component of a fingerprint, while initially sometimes making up over 90% of the weight of the fingerprint, can evaporate quite quickly and may have mostly gone after 24 hours. Following work on the use of argon ion lasers for fingerprint detection,<ref>{{cite journal | last1 = Dalrymple | first1 = BE | author-link = Brian E. Dalrymple | last2 = Duff | first2 = JM | last3 = Menzel | first3 = ER. | year = 1977 | title = Inherent fingerprint luminescence – detection by laser | journal = Journal of Forensic Sciences | volume = 22 | issue = 1| pages = 106–115 | bibcode = 1977SPIE..108..118D | doi = 10.1117/12.955491 | s2cid = 95511647 }}</ref> a wide range of fluorescence techniques have been introduced, primarily for the enhancement of chemically developed fingerprints; the inherent fluorescence of some latent fingerprints may also be detected. Fingerprints can for example be visualized in 3D and without chemicals by the use of infrared lasers.<ref>[https://microscopy-analysis.com/editorials/editorial-listings/spectroscopic-ir-laser-scanner-revealed "Spectroscopic IR laser scanner revealed" in Microscopy & Analysis, July 6, 2018] {{Webarchive|url=https://web.archive.org/web/20181122135630/https://microscopy-analysis.com/editorials/editorial-listings/spectroscopic-ir-laser-scanner-revealed |date=November 22, 2018 }},
[https://patents.google.com/patent/DE102014203918B4/en Google Patent for Patent DE102014203918B4]  concerning
Methode and apparatus for detecting the surface structure and texture of a sample, "Fingerabdruck-Scanner" in pvt. Polizei Verkehr Technik. Fachzeitschrift für Polizei- und Verkehrsmanagement, Technik und Ausstattung 2017, 43, [http://www.rhein-zeitung.de/region/lokales/koblenz_artikel,-koblenzer-unternehmen-digitaler-pinsel-macht-forensik-schneller-_arid,1587553.html "Digitaler Pinsel macht Forensik schneller" in Rhein-Zeitung vom 20. Dezember 2016] {{webarchive|url=https://web.archive.org/web/20170130220607/http://www.rhein-zeitung.de/region/lokales/koblenz_artikel,-koblenzer-unternehmen-digitaler-pinsel-macht-forensik-schneller-_arid,1587553.html |date=January 30, 2017 }}</ref>

A comprehensive manual of the operational methods of fingerprint enhancement was last published by the UK [[Home Office Scientific Development Branch]] in 2013 and is used widely around the world.<ref>[https://www.gov.uk/government/publications/fingerprint-source-book Fingerprint Source Book: manual of development techniques, published 26 March 2013] {{webarchive|url=https://web.archive.org/web/20170211080144/https://www.gov.uk/government/publications/fingerprint-source-book |date=February 11, 2017 }} retrieved on February 9, 2017; see also [https://books.google.com/books?id=-x7fCQAAQBAJ&dq=fingerprints+on+paper&pg=PA21 Max M. Houck (Ed.): Forensic Fingerprints, London 2016, p. 21, 50 er seq.] {{webarchive|url=https://web.archive.org/web/20171228235340/https://books.google.com/books?id=-x7fCQAAQBAJ&lpg=PA56&dq=fingerprints%20on%20paper&hl=de&pg=PA21 |date=December 28, 2017 }}.</ref>

A technique proposed in 2007 aims to identify an individual's [[ethnicity]], [[sex]], and dietary patterns.<ref>{{cite news |last1=Fleming |first1=Nic |title=Fingerprints can reveal race and sex |url=https://www.telegraph.co.uk/news/uknews/1559302/Fingerprints-can-reveal-race-and-sex.html |access-date=October 27, 2018 |work=The Telegraph, AKA [[The Daily Telegraph]], London |publisher=Telegraph Media Group Limited |date=August 3, 2007 |archive-url=https://web.archive.org/web/20150330175441/http://www.telegraph.co.uk/news/uknews/1559302/Fingerprints-can-reveal-race-and-sex.html |archive-date=March 30, 2015 |url-status=live }}</ref>