Editing Perforation (section)

==Applications==
[[File:Stamp US 1954 2c Jefferson coil pair.jpg|right|240px|thumb|Perforation holes on a pair of coil stamps]]
[[File:Paper perforator.jpg|thumb|Paper perforator]]
Perforation frequently refers to the practice of creating a long series of holes or slits so that [[paper]] or [[plastic]]s can be torn more easily along a given line: this is used in easy-open [[packaging]].  Since the creation of perforation devices in the 1840s and 1850s, it has seen use in several areas.

[[Postage stamp]]s are one common application of this, where small round holes are cut in lines to [[postage stamp separation|create individual pieces]]. Perforations on stamps are rather large, in the order of a millimeter, in comparison other perforated materials often have smaller holes.

It is common for [[cheque-book]]s, [[notebook]]s and [[legal pad]]s to have perforations making it easier to tear out individual pages or [[leaf (books)|leaves]]. Perforation is used in ways to separate [[loose leaf]] (or even a form of [[graph paper]] from a [[ringed binder]]). A fine perforation next to the rings allows the page to be separated from the book with no [[confetti]].

[[Screwcap]]s on glass or [[plastic bottle]]s are sealed with a ring at the bottom of the cap attached by perforation. Twisting the cap has the effect of rupturing the material between the perforations and indicating that the original seal has been broken.

[[File:FortranCardPROJ039.agr.jpg|thumb|Perforated punch card]]
The edges of [[film stock]] are perforated to allow it to be moved precise distances at a time continuously.  Similarly, [[punched card]]s for use in [[loom]]s and later in [[computer]]s input and output devices in some cases were perforated to ensure correct positioning of the card in the device, and to encode information.

Perforation of steel strips is used in the manufacture of some [[zester]]s and [[rasp]]s.

Historically, perforation patterns other than linear were used to [[perfin|mark stamps]]. A series of patents had been issued in the late 19th century for perforation machines to be used on rail lines for ticketing. Libraries and private collections used similar perforating stamps to mark ownership of books. End sheets, title pages, and image plates were punched with the namesake of the collection.<ref>{{Cite news|url=http://www.ala.org/lhrt/popularresources/lhrtnewsletters/fall2010|title=LHRT Newsletter|date=2010-12-01|work=Library History Round Table (LHRT)|access-date=2017-06-08|language=en}}</ref> Today, similarly elaborate perforation patterns continue to be used in [[Control point (orienteering)|orienteering]].

Bread bags for some bread often have micro-perforations in the plastic, which is supposed to keep the bread fresh by releasing excess moisture.<ref>{{cite web|url=http://www.clearbags.com/bags/food/micro-perf|title=Micro-Perforated Bags|work=clearbags.com}}</ref> Similarly, bags of concrete use small perforations to allow air to escape while they are being filled.<ref>{{cite web|url=http://www.worldcement.com/product-news/05082015/Weight-of-cement-bags-reduced-by-BSW-Machinery-276/|title=Weight of cement bags reduced by BSW Machinery|work=World Cement|date=5 August 2015 }}</ref>