Editing Envelope (section)

==Manufacture==
{{More citations needed section|date=July 2009}}

===History of envelopes===
[[File:Employement contract IMG 0074.jpg|thumb|Tablet and its sealed envelope: employment contract. [[Girsu]], [[Sumer]], {{circa|2037&nbsp;BC}}. Terra cotta. [[Museum of Fine Arts of Lyon]].]]
[[File:DihuaMarketRat.jpg|thumb|Red envelopes are an example of paper envelopes. They are used for monetary gifts.]]
The first known envelope was nothing like the paper envelope of today. It can be dated back to around 3500 to 3200&nbsp;BC in the ancient Middle East. Hollow clay spheres were molded around financial tokens and used in private transactions. The two people who discovered these first envelopes were [[Jacques de Morgan]], in 1901, and [[Roland de Mecquenem (archaeologist)|Roland de Mecquenem]], in 1907.{{Citation needed|date=May 2022}}

Paper envelopes were developed in China, where paper was invented by the 2nd century BC.<ref name="Tsien">{{Cite journal|last=Tsien|first=Tsuen-Hsuin |author-link=Tsien Tsuen-hsuin |series=Joseph Needham, Science and Civilisation in China, Chemistry and Chemical Technology |volume= 5 part 1|title=Paper and Printing|publisher=Cambridge University Press|year=1985|page=38}}</ref> Paper envelopes, known as ''chih poh'', were used to store gifts of money. In the [[Southern Song]] dynasty, the Chinese imperial court used paper envelopes to distribute monetary gifts to government officials.<ref name="Needham">{{cite book |author=Joseph Needham |author-link=Joseph Needham |title=Science and Civilisation in China: Paper and Printing|url=https://books.google.com/books?id=Lx-9mS6Aa4wC&pg=PA122 |year=1985|publisher=Cambridge University Press|isbn=978-0-521-08690-5|page=122|quote=In the Southern Sung dynasty, gift money for bestowing upon officials by the imperial court was wrapped in paper envelopes (chih pao)}}</ref>

In Western history, from the time flexible writing material became more readily available in the 13th century{{efn | The use of [[History of paper#Papermaking process|waterwheel power for pounding linen, cotton, and flax cloth rags into pulp]] for papermaking dramatically increased the availability of paper. }} until the mid-19th century, correspondence was typically secured by a process of folding and sealing the letter itself,<ref>{{cite web |last1=Cain |first1=Abigail |title=Before Envelopes, People Protected Messages With Letterlocking |url=https://www.atlasobscura.com/articles/what-did-people-do-before-envelopes-letterlocking |website=Atlas Obscura |access-date=20 March 2019 |date=9 November 2018}}</ref> sometimes including elaborate [[letterlocking]] techniques to indicate tampering or prove authenticity.<ref>{{cite web |title=A Letter Sealed for Centuries Has Been Read—Without Even Opening It |url= https://www.wsj.com/articles/a-letter-sealed-for-centuries-has-been-readwithout-even-opening-it-11614679203 |last=Castellanos |first= Sara |date=2 March 2021 |access-date=2 March 2021 |work= The Wall Street Journal }}</ref><ref>{{cite journal |title=Unlocking history through automated virtual unfolding of sealed documents imaged by X-ray microtomography |last1=Dambrogio |first1=Jana |last2=Ghassaei |first2=Amanda |last3=Staraza Smith |first3=Daniel |last4=Jackson |first4=Holly |last5=Demaine |first5=Martin L.|date=2 March 2021 |journal=Nature Communications |volume=12 |issue=1 |page=1184 |doi=10.1038/s41467-021-21326-w |pmid=33654094 |pmc=7925573 |bibcode= 2021NatCo..12.1184D}}</ref> Some of these letter techniques, which could involve stitching or wax seals, were also employed to secure hand-made envelopes.
[[File:Backside of envelope stamped 1841.jpg|thumb|Reverse of envelope (possibly machine-cut) stamped 1841]]
[[File:Frontside of envelope from 1841.jpg|thumb|Front of an envelope mailed in 1841. Stamp from 1841 on backside. Possibly machine cut.]]
Prior to 1840, all envelopes were handmade, including those for commercial use. In 1840 George Wilson of London was granted a patent for an envelope-cutting machine (patent: "an improved paper-cutting machine");<ref>The Repertory of Patent Inventions, and other Discoveries & Improvements in Arts, Manufactures and Agriculture; being a continuation, on an enlarged plan of the Repertory of Arts & Manufactures. New Series. - VOL. XIII, January–June, 1840. London: Published by the Proprietor, J. S. Hodson. 112, Flett Street. (p. 107) Patent of January 21, 1840 (This is page 107 under the heading "List of New Patents"

Kategorier</ref> these machine-cut envelopes still needed to be folded by hand.<ref>The Royal Commission (1851). ''Great Exhibition of the Works of Industry of all Nations, 1851. Official Descriptive and Illustrated Catalogue.'' London: William Clowes and Sons (s. 542-543)</ref><ref>Practical Mechanic's Journal and Patent Office (1850). The Practical Mechanics Journal, Volume II - April 1849 - March 1850. Glasgow, London and New York (p.169-170)</ref> There is a picture of the front and backside of an envelope stamped in 1841 here on this page. It seems to be machine cut. In 1845, [[Edwin Hill (United Kingdom)|Edwin Hill]] and [[Warren De La Rue]] were granted a British patent for the first envelope-folding machine.<ref>{{cite web|url=http://www.makingthemodernworld.org.uk/stories/the_age_of_the_engineer/03.ST.03/?scene=7&tv=true |title=The Heroic Age |publisher=Making the Modern World |access-date=6 November 2012}}</ref>

The "envelopes" produced by the Hill/De La Rue machine were not like those used today. They were flat diamond, lozenge (or [[rhombus]])-shaped sheets or "blanks" that had been precut to shape before being fed to the machine for creasing and made ready for folding to form a rectangular enclosure. The edges of the overlapping flaps treated with a paste or [[adhesive]] and the method of securing the envelope or wrapper was a user choice. The symmetrical flap arrangement meant that it could be held together with a single wax seal at the apex of the topmost flap. (That the flaps of an envelope can be held together by applying a seal at a single point is a classic design feature of an envelope.){{citation needed|date=December 2011}}

Nearly 50 years passed before a commercially successful machine for producing pre-gummed envelopes, like those in use today, appeared.{{Citation needed|date=May 2022}}

The origin of the use of the diamond shape for envelopes is debated.{{By whom|date=May 2022}} However, as an alternative to simply wrapping a sheet of paper around a folded letter or an invitation and sealing the edges, it is a tidy and ostensibly paper-efficient way of producing a rectangular-faced envelope. Where the claim to be paper-efficient fails is a consequence of paper manufacturers normally making paper available in rectangular sheets, because the largest size of envelope that can be realised by cutting out a diamond or any other shape which yields an envelope with symmetrical flaps is smaller than the largest that can be made from that sheet simply by folding.

[[File:Envelope - Wood Food Company-000.jpg|thumb|left|Envelope with advertising from 1905 used in the U.S.]]
The folded diamond-shaped sheet (or "blank") was in use at the beginning of the 19th century as a novelty wrapper for invitations and letters among the proportion of the population that had the time to sit and cut them out and were affluent enough not to bother about the waste offcuts.{{Citation needed|date=May 2022}} Their use first became widespread in the UK when the British government took monopoly control of postal services and tasked [[Rowland Hill (postal reformer)|Rowland Hill]] with its introduction. The new service was launched in May 1840 with a postage-paid machine-printed illustrated (or pictorial) version of the wrapper and the much-celebrated first adhesive postage stamp, the [[Penny Black]], for the production of which the [[Jacob Perkins]] printing process was used to deter counterfeiting and forgery. The wrappers were printed and sold as a sheet of 12, with cutting the purchaser's task. Known as [[Mulready stationery]], because the illustration was created by the respected artist [[William Mulready]], the envelopes were withdrawn when the illustration was ridiculed and lampooned. Nevertheless, the public apparently saw the convenience of the wrappers being available ready-shaped, and it must have been obvious that with the stamp available totally plain versions of the wrapper could be produced and postage prepaid by purchasing a stamp and affixing it to the wrapper once folded and secured.  In this way although the postage-prepaid printed pictorial version died ignominiously, the diamond-shaped wrapper acquired de facto official status and became readily available to the public notwithstanding the time taken to cut them out and the waste generated. With the issuing of the stamps and the operation and control of the service (which is a communications medium) in government hands the British model spread around the world and the diamond-shaped wrapper went with it.

Hill also installed his brother Edwin as The Controller of Stamps, and it was he with his partner Warren De La Rue who patented the machine for mass-producing the diamond-shaped sheets for conversion to envelopes in 1845. Today, envelope-making machine manufacture is a long- and well-established international industry, and blanks are produced with a short-arm-cross shape and a kite shape as well as diamond shape. (The short-arm-cross style is mostly encountered in "pocket" envelopes i.e. envelopes with the closing flap on a short side. The more common style, with the closing flap on a long side, are sometimes referred to as "standard" or "wallet" style for purposes of differentiation.)

[[File:Blythe House Envelope-making machines 1930s.JPG|thumb|Envelope-making machines at the Post Office Savings Bank, Blythe House, [[West Kensington]], [[London]]]]
[[File:Machine Envelope Printer.jpg|thumb|Machine Envelope Printer was one of the machine presses at the [[Bulaq Press]]. It is now in [[Bibliotheca Alexandrina]]]]
The most famous paper-making machine was the [[Fourdrinier machine]]. The process involves taking processed pulp stock and converting it to a continuous web which is gathered as a reel.  Subsequently, the reel is guillotined edge to edge to create a large number of properly rectangular sheets because ever since the invention of [[Gutenberg press|Gutenberg's press]] paper has been closely associated with printing.

To this day, all other mechanical printing and duplicating equipments devised in the meantime, including the [[typewriter]] (which was used up to the 1990s for addressing envelopes), have been primarily designed to process rectangular sheets. Hence the large sheets are in turn guillotined down to the sizes of rectangular sheet commonly used in the commercial [[printing]] industry, and nowadays to the sizes commonly used as feed-stock in office-grade computer printers, copiers and duplicators (mainly ISO, A4 and US Letter).

Using any mechanical printing equipment to print on envelopes, which although rectangular, are in fact folded sheets with differing thicknesses across their surfaces, calls for skill and attention on the part of the operator. In commercial printing the task of printing on machine-made envelopes is referred to as "overprinting" and is usually confined to the front of the envelope. If printing is required on all four flaps as well as the front, the process is referred to as "printing on the flat". Eye-catching [[illustrated envelopes]] or [[pictorial envelopes]], the origins of which as an artistic genre can be attributed to the Mulready stationery – and which was printed in this way – are used extensively for [[direct mail]]. In this respect, direct mail envelopes have a shared history with [[propaganda]] envelopes (or "[[Cover (philately)|covers]]") as they are called by philatelists.{{Citation needed|date=May 2022}}

===Present and future state of envelopes===
In 1998, the [[U.S. Postal Service]] became the first postal authority to approve a system of printing digital stamps.{{Citation needed|date=May 2022}} With this innovative alternative to an adhesive-backed [[postage stamp]], businesses could more easily produce envelopes in-house, address them, and customize them with advertising information on the face.
[[File:Mail_Sample_(back_to_back).jpg|thumb|Mail envelope certified by [[Philippine Postal Corporation|PHLPost]]]]
The fortunes of the commercial envelope manufacturing industry and the postal service go hand in hand, and both link to the printing industry and the mechanized envelope processing industry producing equipment such as franking and addressing machines. Technological developments affecting one ricochet through the others: addressing machines print addresses, postage stamps are a print product, franking machines imprint a frank on an envelope. If fewer envelopes are required; fewer stamps are required; fewer franking machines are required and fewer addressing machines are required.{{Citation needed|date=June 2008}} For example, the advent of information-based indicia (IBI) (commonly referred to as digitally-encoded electronic stamps or digital indicia) by the US Postal Service in 1998 caused widespread consternation in the franking machine industry, as their machines were rendered obsolete, and resulted in a flurry of lawsuits involving Pitney Bowes among others. The advent of [[e-mail]] in the late 1990s appeared to offer a substantial threat to the postal service. By 2008 letter-post service operators were reporting significantly smaller volumes of letter-post, specifically stamped envelopes, which they attributed mainly to e-mail. Although a corresponding reduction in the volume of envelopes required would have been expected, no such decrease was reported as widely as the reduction in letter-post volumes.