An envelope is a common packaging item, usually made of thin, flat material. It is designed to contain a flat object, such as a letter or card.
Traditional envelopes are made from sheets of paper cut to one of three shapes: a rhombus, a short-arm cross or a kite. These shapes allow the envelope structure to be made by folding the sheet sides around a central rectangular area. In this manner, a rectangle-faced enclosure is formed with an arrangement of four flaps on the reverse side.
Overview
A folding sequence such that the last flap closed is on a short side is referred to in commercial envelope manufacture as a pocket – a format frequently employed in the packaging of small quantities of seeds. Although in principle the flaps can be held in place by securing the topmost flap at a single point (for example with a wax seal), generally they are pasted or gummed together at the overlaps. They are most commonly used for enclosing and sending mail (letters) through a prepaid-postage postal system.
Window envelopes have a hole cut in the front side that allows the paper within to be seen. They are generally arranged so that the receiving address printed on the letter is visible, saving duplication of the address on the envelope itself. The window is normally covered with a transparent or translucent film to protect the letter inside, as was first designed by Americus F. Callahan in 1901 and patented the following year. there is no international standard for window envelopes, but some countries, including Germany and the United Kingdom, have national standards.
An aerogram is related to a letter sheet, both being designed to have writing on the inside to minimize the weight. Any handmade envelope is effectively a letter sheet because prior to the folding stage it offers the opportunity for writing a message on that area of the sheet that after folding becomes the inside of the face of the envelope. For document security, the letter sheet can be sealed with wax. Another secure form of letter sheet is a locked letter that is formed by cutting and folding the sheet in an elaborate way that prevents the letter from being opened without creating obvious damage to the letter/envelope.
The "envelope" used to launch the Penny Post component of the British postal reforms of 1840 by Sir Rowland Hill and the invention of the postage stamp was a lozenge-shaped lettersheet known as a Mulready. If desired, a separate letter could be enclosed with postage remaining at one penny provided the combined weight did not exceed half an ounce (14 grams). This was a legacy of the previous system of calculating postage, which partly depended on the number of sheets of paper used.
During the U.S. Civil War those in the Confederate States Army occasionally used envelopes made from wallpaper, due to financial hardship.
A "return envelope" is a pre-addressed, smaller envelope included as the contents of a larger envelope and can be used for courtesy reply mail, metered reply mail, or freepost (business reply mail). Some envelopes are designed to be reused as the return envelope, saving the expense of including a return envelope in the contents of the original envelope. The direct mail industry makes extensive use of return envelopes as a response mechanism.
Up until 1840, all envelopes were handmade, each being individually cut to the appropriate shape out of an individual rectangular sheet. In that year George Wilson in the United Kingdom patented the method of tessellating (tiling) a number of envelope patterns across and down a large sheet, thereby reducing the overall amount of waste produced per envelope when they were cut out. In 1845 Edwin Hill and Warren de la Rue obtained a patent for a steam-driven machine that not only cut out the envelope shapes but creased and folded them as well. (Mechanised gumming had yet to be devised.) The convenience of the sheets ready cut to shape popularized the use of machine-made envelopes, and the economic significance of the factories that had produced handmade envelopes gradually diminished.
As envelopes are made of paper, they are intrinsically amenable to embellishment with additional graphics and text over and above the necessary postal markings. This is a feature that the direct mail industry has long taken advantage of—and more recently the mail art movement. Custom printed envelopes have also become an increasingly popular marketing method for small businesses.
Since the early 20th century, mechanical folding machines have been the basis of envelope production.
Sizes
International standard sizes International standard ISO 269 (withdrawn in 2009 without replacement) defined several standard envelope sizes, which are designed for use with ISO 216 standard paper sizes:
+ International standard envelope sizes Format Dimensions (mm) Dimensions (in) AR Suitable content format DL A4 C7 A7 (or A6) C7/C6 A5 C6 A6 (or A5 or A4) C6/C5 A4 C5 A5 (or A4) C4 A4 C3 A3 B6 C6 B5 C5 B4 C4 E4 B4 The German standard DIN 678 defines a similar list of envelope formats.
DL comes from the DIN Lang (German: "Long") size envelope which originated in the 1920s.
North American sizes There are dozens of sizes of envelopes available in the United States.
The designations such as "A2" do not correspond to ISO paper sizes. Sometimes, North American paper jobbers and printers will insert a hyphen to distinguish from ISO sizes, thus: A-2.
+ North American standard envelope sizes Format Dimensions (in) Dimensions (mm) Suitable content format A2 (Lady Grey) Letter paper folded twice () A6 (Thompson Standard) A2 A7 (Besselheim) A6 A8 (Carrs) A7 A9 (Diplomat) Letter paper folded once (), A8 A10 (Willow) C5 No. (Personal) Personal check, US currency No. (Monarch) No. 9 (A long) No. 10 (Business, Commercial) No. 9; letter paper folded into thirds () No. 11 No. 10 No. 12 No. 11 No. 14 No. 12
The No. 10 envelope is the standard business envelope size in the United States. PWG 5101.1 also lists the following even inch sizes for envelopes: , , , , , and .
Envelopes accepted by the U.S. Postal Service for mailing at the price of a letter must be:
Rectangular At least inches high × 5 inches long × 0.007 inch thick. No more than inches high × inches long × inch thick. Letters that have a length-to-height aspect ratio of less than 1.3 or more than 2.5 are classified as "non-machinable" by the USPS and may cost more to mail.
Chinese sizes
+ Chinese envelope sizesPWG 5101.1 Format Dimensions (mm) Dimensions (in) Suitable content format PRC1 Chinese #1 Envelope PRC2 Chinese #2 Envelope PRC3, ISO B6 Chinese #3 Envelope C6 PRC4 Chinese #4 Envelope PRC6 Chinese #6 Envelope A4 folded once () PRC7 Chinese #7 Envelope A5 (rounded ISO C5) PRC8 Chinese #8 Envelope A4 folded once () PRC10, ISO C3 Chinese #10 Envelope A3
Japanese sizes Japanese traditional rectangular (角形, kakugata, K) and long (長形, nagagata, N) envelopes open on the short side, while Western-style (洋形, yōgata, Y) envelopes open on the long side.
The Japanese standard JIS S 5502JIS S 5502:2010 Envelopes, translated was first published in 1964. Some traditional sizes were not kept and some sizes have been removed until its latest edition in 2014, leaving behind gaps in the numeric sequence of designations.
+ Japanese envelopes Format Standard Dimensions (mm) Dimensions (in) Suitable content format Kaku A3 A3 Kaku 0 K0 B4 Kaku 1 K1 B4 Kaku 2 K2 A4 Kaku 20 K20 A4 Kaku 3 K3 B5 Kaku 4 K4 B5 Kaku 5 K5 A5 Kaku 6 K6 A5 Kaku 7 K7 B6 Kaku 8 K8 salaries, wages Chou 1 N1 A4 folded in half lengthwise Chou 2 N2 B5 folded in half lengthwise Chou 3 N3 A4 folded in thirds Chou 30 N30 A4 folded in fourths Chou 4 N4 JIS B5 folded in fourths Chou 40 N40 A4 folded in fourths N6 A4 folded in thirds You 0, You 8 Y0 kyabine (cabinet) size photos () You 1 Y1 C6, You 2 You 2 Y2 A6 (), Hagaki You 3 Y3 JIS B7 () You 4 (Chou 31) Y4 A4 folded in thirds (), You 5 You 5 Y5 A4 folded in fourths () You 6 Y6 You 7 Y7 JIS B7
Manufacture
History of envelopes
The first known envelope was nothing like the paper envelope of today. It can be dated back to around 3500 to 3200 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, in 1907.
Paper envelopes were developed in China, where paper was invented by the 2nd century BC. Paper envelopes known as zhibao 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.
In Western history, from the time flexible writing material became more readily available in the 13th century until the mid-19th century, correspondence was typically secured by a process of folding and sealing the letter itself, sometimes including elaborate letterlocking techniques to indicate tampering or prove authenticity. Some of these letter techniques, which could involve stitching or wax seals, were also employed to secure hand-made envelopes.
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");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 these machine-cut envelopes still needed to be folded by hand.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)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) In 1845, Edwin Hill and Warren De La Rue were granted a British patent for the first envelope-folding machine.
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.
Self-gumming envelope-folding machines closer to those in use today were developed in the late 1860s beginning with Thomas Waymouth's machine for Berlin & Jones, and improved by the brothers Henry and Daniel Swift, whose design could gum envelopes without worker assistance.
As an alternative to simply wrapping a sheet of paper around a folded letter or an invitation and sealing the edges, the diamond shape is a tidy, paper-efficient way of producing a rectangular-faced envelope.