Editing Fingerprint (section)

== Biology ==
[[File:Fingerprint detail on male finger in Třebíč, Třebíč District.jpg|thumb|left|The friction ridges on a finger]]

Fingerprints are impressions left on surfaces by the friction ridges on the finger of a human.<ref>{{Cite book|title=Biologically Rationalized Computing Techniques For Image Processing Applications|editor=Jude Hemanth & Valentina Emilia Balas|publisher=Springer|year=2018|isbn=978-3319613161|pages=116}}</ref> The matching of two fingerprints is among the most widely used and most reliable [[biometric]] techniques. Fingerprint matching considers only the obvious features of a fingerprint.<ref name="auto">{{Cite book|title=Encyclopedia of Biometrics: I–Z Volume 2|author=Stan Z. Li|publisher=Springer Science & Business Media |year=2009|isbn=978-0387730028|pages=439}}</ref>

The composition of fingerprints consists of water (95%-99%), as well as organic and inorganic constituents.<ref name=":4">{{Cite journal |last1=Cadd |first1=Samuel |last2=Islam |first2=Meez |last3=Manson |first3=Peter |last4=Bleay |first4=Stephen |date=2015-07-01 |title=Fingerprint composition and aging: A literature review |url=https://www.sciencedirect.com/science/article/pii/S1355030615000131 |journal=Science & Justice |language=en |volume=55 |issue=4 |pages=219–238 |doi=10.1016/j.scijus.2015.02.004 |pmid=26087870 |issn=1355-0306}}</ref> The organic component is made up of amino acids, proteins, glucose, lactase, urea, pyruvate, fatty acids and sterols.<ref name=":4" />  Inorganic ions such as chloride, sodium, potassium and iron are also present.<ref name=":4" /> Other contaminants such as oils found in cosmetics, drugs and their metabolites and food residues may be found in fingerprint residues.<ref>{{Cite journal |last1=Khare |first1=Vartika |last2=Singla |first2=Anu |date=2022-01-27 |title=A review on the advancements in chemical examination of composition of latent fingerprint residues |journal=Egyptian Journal of Forensic Sciences |volume=12 |issue=1 |pages=6 |doi=10.1186/s41935-021-00262-2 |s2cid=246292738 |issn=2090-5939 |doi-access=free }}</ref>

A friction ridge is a raised portion of the [[epidermis (skin)|epidermis]] on the digits (fingers and [[toe]]s), the palm of the hand or the [[Sole (foot)|sole]] of the foot, consisting of one or more connected ridge units of friction ridge skin.{{citation needed|date=June 2019}} These are sometimes known as "epidermal ridges" which are caused by the underlying interface between the [[dermal papillae]] of the dermis and the interpapillary (rete) pegs of the epidermis. These unique features are formed at around the 15th week of fetal development and remain until after death, when decomposition begins.<ref name=":02">{{Cite journal |last=Ashbaugh |first=David |date=1991 |title=Ridgeology |url=https://chance.dartmouth.edu/chance_news/for_chance_news/ChanceNews12.05/ridgeology.pdf |journal=Journal of Forensic Identification |volume=41 |issue=1 |pages=16–64}}</ref> During the development of the fetus, around the 13th week of a pregnancy, ledge-like formation is formed at the bottom of the epidermis beside the dermis.<ref name=":02" /> The cells along these ledges begin to rapidly proliferate.<ref name=":02" /> This rapid proliferation forms primary and secondary ridges.<ref name=":02" /> Both the primary and secondary ridges act as a template for the outer layer of the skin to form the friction ridges seen on the surface of the skin.<ref name=":02" />

These epidermal ridges serve to amplify [[vibration]]s triggered, for example, when fingertips brush across an uneven surface, better transmitting the signals to [[sensory nerve]]s involved in fine texture perception.<ref>{{cite journal | author= Roberta Kwok | url= http://www.nature.com/news/2009/090129/full/news.2009.68.html | date= 29 January 2009 | journal= [[Nature (journal)|Nature]] | title= Fake finger reveals the secrets of touch | doi= 10.1038/news.2009.68 | access-date= January 30, 2009 | archive-date= January 31, 2009 | archive-url= https://web.archive.org/web/20090131063524/http://www.nature.com/news/2009/090129/full/news.2009.68.html | url-status= live }}</ref> These ridges may also assist in gripping rough surfaces and may improve surface contact in wet conditions.<ref>{{Cite news|url = http://news.bbc.co.uk/2/hi/health/8093134.stm|title = Fingerprint grip theory rejected|publisher = BBC|date = 12 June 2009|access-date = June 16, 2009|archive-date = June 16, 2009|archive-url = https://web.archive.org/web/20090616084922/http://news.bbc.co.uk/2/hi/health/8093134.stm|url-status = live}}</ref>