Envelope

# Envelope

Discussion

Encyclopedia
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
Greeting card
A greeting card is an illustrated, folded card featuring an expression of friendship or other sentiment. Although greeting cards are usually given on special occasions such as birthdays, Christmas or other holidays, they are also sent to convey thanks or express other feeling. Greeting cards,...

.

Traditional envelopes are made from sheets of paper cut to one of three shapes: a rhombus
Rhombus
In Euclidean geometry, a rhombus or rhomb is a convex quadrilateral whose four sides all have the same length. The rhombus is often called a diamond, after the diamonds suit in playing cards, or a lozenge, though the latter sometimes refers specifically to a rhombus with a 45° angle.Every...

, a short-arm cross, or a kite. These shapes allow for the creation of the envelope structure 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

When the folding sequence is such that the last flap to be closed is on a short side it 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
Mail
Mail, or post, is a system for transporting letters and other tangible objects: written documents, typically enclosed in envelopes, and also small packages are delivered to destinations around the world. Anything sent through the postal system is called mail or post.In principle, a postal service...

(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 sending address printed on the letter is visible, saving the sender from having to duplicate 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
Americus Callahan
A windowed envelope is a conventional envelope with a plastic window to allow the recipient's address to be printed on the paper contained within.-History:...

in 1901 and patented the following year. In some cases, shortages of materials or the need to economize resulted in envelopes that had no film covering the window. One innovative process, invented in Europe about 1905, involved using hot oil to saturate the area of the envelope where the address would appear. The treated area became sufficiently translucent for the address to be readable. there is no international standard for window envelopes, but some countries, including Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

and the UK, have national standards.

Security envelopes have a patterned tint printed on the inside, which makes it difficult to see the contents. Various patterns exist.

An aerogram
Aerogram
An Aerogram, Aérogramme or Air Letter is a thin lightweight piece of foldable and gummed paper for writing a letter for transit via airmail, in which the letter and envelope are one and the same. Most postal administrations forbid enclosures in these light letters, which are usually sent abroad at...

is related to a lettersheet, both being designed to have writing on the inside to minimize the weight. Any handmade envelope is effectively a lettersheet 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.

The "envelope" used to launch the Penny Post component of the British
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

postal reforms of 1840 by Sir Rowland Hill
Rowland Hill (postal reformer)
Sir Rowland Hill KCB, FRS was an English teacher, inventor and social reformer. He campaigned for a comprehensive reform of the postal system, based on the concept of penny postage and his solution of prepayment, facilitating the safe, speedy and cheap transfer of letters...

and the invention of the postage stamp
Postage stamp
A postage stamp is a small piece of paper that is purchased and displayed on an item of mail as evidence of payment of postage. Typically, stamps are made from special paper, with a national designation and denomination on the face, and a gum adhesive on the reverse side...

, was a lozenge-shaped lettersheet known as a Mulready
Mulready stationery describes the postal stationery lettersheets and pre-gummed envelopes that were introduced as part of the British Post Office postal reforms of 1840. They went on sale on 1 May, 1840, and were valid for use from 6 May...

. If desired, a separate letter could be enclosed with postage remaining at one penny provided the combined weight did not exceed half an ounce (about 13 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
Confederate States Army
The Confederate States Army was the army of the Confederate States of America while the Confederacy existed during the American Civil War. On February 8, 1861, delegates from the seven Deep South states which had already declared their secession from the United States of America adopted the...

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
Metered reply mail, or MRM, is a type of mail in which a business sends pre-printed, self-addressed envelopes or postcards to customers, with postage prepaid on the envelopes or postcards with a postage meter...

, or freepost
Freepost
Freepost is a postal service provided by various postal administrations, whereby a person sends mail without affixing postage, and the recipient pays the postage when collecting the mail...

(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
Direct mail
Advertising mail, also known as direct mail, junk mail, or admail, is the delivery of advertising material to recipients of postal mail. The delivery of advertising mail forms a large and growing service for many postal services, and direct-mail marketing forms a significant portion of the direct...

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
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

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
Edwin Hill (U.K.)
Edwin Hill was a Victorian postal official, the older brother of Rowland Hill, who invented a mechanical system to make envelopes and who campaigned for legal and political change.- Early life :...

and Warren de la Rue
Warren de la Rue
Warren De la Rue was a British astronomer and chemist, most famous for his pioneering work in astronomical photography.-Biography:...

obtained a patent
Patent
A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....

for a steam
Steam
Steam is the technical term for water vapor, the gaseous phase of water, which is formed when water boils. In common language it is often used to refer to the visible mist of water droplets formed as this water vapor condenses in the presence of cooler air...

-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
Direct mail
Advertising mail, also known as direct mail, junk mail, or admail, is the delivery of advertising material to recipients of postal mail. The delivery of advertising mail forms a large and growing service for many postal services, and direct-mail marketing forms a significant portion of the direct...

industry has long taken advantage of—and more recently the Mail Art
Mail art
Mail art is a worldwide cultural movement that began in the early 1960s and involves sending visual art through the international postal system. Mail Art is also known as Postal Art or Correspondence Art...

movement. Custom printed envelopes has also become an increasingly popular marketing method for small business
A small business is a business that is privately owned and operated, with a small number of employees and relatively low volume of sales. Small businesses are normally privately owned corporations, partnerships, or sole proprietorships...

.

Most of the over 400 billion envelopes of all sizes made worldwide are machine-made.

### International standard sizes

International standard
International standard
International standards are standards developed by international standards organizations. International standards are available for consideration and use, worldwide...

ISO 269 defines several standard envelope sizes, which are designed for use with ISO 216
ISO 216
ISO 216 specifies international standard paper sizes used in most countries in the world today. It defines the "A" and "B" series of paper sizes, including A4, the most commonly available size...

standard paper sizes:
Format Dimensions (HxW mm) Suitable for content format
DL 110 × 220 1/3 A4
C7/C6 81 x 162 1/3 A5
C6 114 × 162 A6 (or A4 folded in half twice)
C6/C5 114 × 229 1/3 A4
C5 162 × 229 A5 (or A4 folded in half once)
C4 229 × 324 A4
C3 324 × 458 A3
B6 125 × 176 C6
B5 176 × 250 C5
B4 250 × 353 C4
E4 280 × 400 B4

The German standard DIN
Din
DIN or Din or din can have several meanings:* A din is a loud noise.* Dīn, an Arabic term meaning "religion" or "way of life".* Din is one of the ten aspects of the Ein Sof in Kabbalah ....

678 defines a similar list of envelope formats.

### North American sizes

There are dozens of sizes of envelopes available. Not all are used for posting mail, but for such things as former pay packets or putting a gift card or a key in. U.S. and Canadian postal regulations differ from those of the rest of the world; although envelopes are still deliverable worldwide by the regulations of the Universal Postal Union
Universal Postal Union
The Universal Postal Union is an international organization that coordinates postal policies among member nations, in addition to the worldwide postal system. The UPU contains four bodies consisting of the Congress, the Council of Administration , the Postal Operations Council and the...

, the sorting machines will not accept the international sizes. This is not as much a difference as usually thought, for the location of sending address and return address differ between Germany and France, for example.

The names of the envelopes were suggested by Abraham Lincoln
Abraham Lincoln
Abraham Lincoln was the 16th President of the United States, serving from March 1861 until his assassination in April 1865. He successfully led his country through a great constitutional, military and moral crisis – the American Civil War – preserving the Union, while ending slavery, and...

during the American Civil War
American Civil War
The American Civil War was a civil war fought in the United States of America. In response to the election of Abraham Lincoln as President of the United States, 11 southern slave states declared their secession from the United States and formed the Confederate States of America ; the other 25...

in order to hide that letters were being sent to Union commanders.

The designations such as "A2" do not correspond to ISO paper sizes.
Format Dimensions (in) Dimensions (mm) Ratio
A2 (Lady Grey) 4⅜ × 5¾ 111.1 × 146.1 132%
A6 (Thompson's standard) 4¾ × 6½ 120.7 × 165.1 137%
A7 (Besselheim) 5¼ × 7¼ 133.4 × 184.2 138%
A8 (Carr's) 5½ × 8⅛ 139.7 × 206.4 148%
A9 (Diplomat) 5¾ × 8¾ 146.1 × 222.3 152%
A10 (Willow) 6 × 9½ 152.4 × 241.3 158%
No. 6¾ (Lady Chapham) 3⅝ × 6½ 92.1 × 165.1 179%
No. 7¾ (Monarch) 3⅞ × 7½ 98.4 × 190.5 194%
No. 9 (Windsor) 3⅞ × 8⅞ 98.4 × 225.4 229%
No. 10 (Tairy Greene) 4⅛ × 9½ 104.8 × 241.3 230%
No. 11 (Business Formal) 4½ × 10⅜ 114.3 × 263.5 231%
No. 12 (Business Casual) 4¾ × 11 120.7 × 279.4 232%
No. 14 (Business Nude) 5 × 11½ 127.0 × 292.1 230%

##### Envelopes accepted by the U.S. Postal Service to be eligible for mailing at the price for letters must be
• Rectangular
• At least 3-1/2 inches high x 5 inches long x 0.007 inch thick.
• No more than 6-1/8 inches high x 11-1/2 inches long x 1/4 inch thick.

## Manufacture

Nearly half of the estimated 450 billion envelopes made each year worldwide are machine-made.

### History of envelopes

Prior to 1845, hand-made envelopes were all that were available for use, both commercial and domestic. In 1845, Edwin Hill and Warren De La Rue
Warren de la Rue
Warren De la Rue was a British astronomer and chemist, most famous for his pioneering work in astronomical photography.-Biography:...

were granted a British patent for the first envelope-making machine.

The first known envelope was nothing like the paper envelope we know of today. It can be dated back to around 3500 to 3200 B.C. 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
Jacques de Morgan
Jean-Jacques de Morgan was a French mining engineer , geologist, and archaeologist. He was the director of Antiquities in Egypt during the 19th century , and excavated in Memphis and Dashur, providing many drawings of many Egyptian pyramids...

, in 1901, and Roland de Mecquenem
Roland de Mecquenem (archaeologist)
Roland de Mecquenem was a French archaeologist who took part in the excavations of Susa in Iran.He was a graduate of the Ecole des Mines.-External links:...

, in 1907.

The "envelopes" produced by the Hill/De La Rue machine were not as we know them today. They were flat diamond, lozenge (or rhombus
Rhombus
In Euclidean geometry, a rhombus or rhomb is a convex quadrilateral whose four sides all have the same length. The rhombus is often called a diamond, after the diamonds suit in playing cards, or a lozenge, though the latter sometimes refers specifically to a rhombus with a 45° angle.Every...

)-shaped sheets or "blanks" which 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
An adhesive, or glue, is a mixture in a liquid or semi-liquid state that adheres or bonds items together. Adhesives may come from either natural or synthetic sources. The types of materials that can be bonded are vast but they are especially useful for bonding thin materials...

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).

Nearly 50 years passed before a commercially successful machine for producing pre-gummed envelopes effectively as we know them today appeared.

The origin of the use of the diamond shape for envelopes is debated. 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.

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 segment of the population that had the time to sit and cut them out and were affluent enough not to bother about the waste offcuts. Their use first became widespread in the UK when the British government took monopoly control of postal services and tasked Rowland Hill
Rowland Hill (postal reformer)
Sir Rowland Hill KCB, FRS was an English teacher, inventor and social reformer. He campaigned for a comprehensive reform of the postal system, based on the concept of penny postage and his solution of prepayment, facilitating the safe, speedy and cheap transfer of letters...

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
Penny Black
The Penny Black was the world's first adhesive postage stamp used in a public postal system. It was issued in Britain on 1 May 1840, for official use from 6 May of that year....

- for the production of which the Jacob Perkins
Jacob Perkins
Jacob Perkins was an Anglo-American inventor, mechanical engineer and physicist. Born in Newburyport, Massachusetts, Perkins was apprenticed to a goldsmith...

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
Mulready stationery describes the postal stationery lettersheets and pre-gummed envelopes that were introduced as part of the British Post Office postal reforms of 1840. They went on sale on 1 May, 1840, and were valid for use from 6 May...

, because the illustration was created by the respected artist William Mulready
William Mulready was an Irish genre painter living in London. He is best known for his romanticizing depictions of rural scenes, and for creating Mulready stationery letter sheets, issued at the same time as the Penny Black postage stamp.-Life and family:William Mulready was born in Ennis, County...

, 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.)

The most famous paper-making machine was the Fourdrinier machine
Fourdrinier machine
This article contains a glossary section at the end.Most modern papermaking machines are based on the principles of the Fourdrinier Machine. It has been used in some variation since its inception...

. 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'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
Typewriter
A typewriter is a mechanical or electromechanical device with keys that, when pressed, cause characters to be printed on a medium, usually paper. Typically one character is printed per keypress, and the machine prints the characters by making ink impressions of type elements similar to the pieces...

(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 are guillotined down to the sizes of rectangular sheet commonly used in the commercial printing
Printing
Printing is a process for reproducing text and image, typically with ink on paper using a printing press. It is often carried out as a large-scale industrial process, and is an essential part of publishing and transaction 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
Mulready stationery describes the postal stationery lettersheets and pre-gummed envelopes that were introduced as part of the British Post Office postal reforms of 1840. They went on sale on 1 May, 1840, and were valid for use from 6 May...

- and which was printed in this way - are used extensively for direct mail
Direct mail
Advertising mail, also known as direct mail, junk mail, or admail, is the delivery of advertising material to recipients of postal mail. The delivery of advertising mail forms a large and growing service for many postal services, and direct-mail marketing forms a significant portion of the direct...

. In this respect, direct mail envelopes have a shared history with propaganda
Propaganda
Propaganda is a form of communication that is aimed at influencing the attitude of a community toward some cause or position so as to benefit oneself or one's group....

envelopes (or "covers
Cover (philately)
In philately, the term cover pertains to the outside of an envelope or package with an address, typically with postage stamps that have been cancelled and is a term generally used among stamp and postal history collectors. The term does not include the contents of the letter or package, although...

") as they are called by philatelists.

At the end of the 20th century a top of the range envelope-making machine cost in the region of \$1 million and could produce 1200 pre-gummed envelopes per minute in boxes of 1000 ready for distribution. With manufacturing costs as high as this very few envelope-making machinery manufacturers appeared in the 19th and 20th centuries, and at the beginning of the 21st century the number satisfying the world demand remained low, with a single enterprise, Winkler+Dünnebier, producing two-thirds of the machines producing the 450 billion envelopes referred to above (which includes "pockets").

Consequently too the high cost of buying these high capital investment machines has to be factored into the operating costs of any enterprise which engages in producing printed envelopes, and so their line of business is the production of very large runs of the order of 50,000 and upwards. Depending on the size of the run this can entail the use of an entire web or reel. The result of this is that over the last 150 years or so the most common way of producing printed envelopes commercially has been to overprint on machine-made envelopes. Needless to say, only the largest of companies have a need for 50,000 or more envelopes at any one time. The drawback is that although printing on the face of an envelope is reasonably straight- forward, an envelope is not a flat sheet of paper and so if printing is required on one or more flaps this incurs higher cost as specialist printing skill is required. For small businesses with a need for relatively low volumes of printed envelopes, even if a case is made for a batch customised with no more than the company logo on the face, there is seldom justification for the added expense of printing on the flap side too. However the volume-related barrier to the use of customised envelopes by small businesses was subsequently lowered in the late-20th century with the advent of the digital printing revolution which saw the introduction of PC printers. Although designed primarily to process flat rectangular sheets these could be adjusted to also overprint on the face of rectangular machine-made envelopes in spite of the extra thickness - given suitable office applications software such as Microsoft's Word.

### Present and future state of envelopes

Then right at the end of the 20th century, in 1998, the digital printing revolution delivered another benefit for small businesses when the U.S. Postal Service became the first postal authority to approve the introduction of a system of applying to an envelope in the printer bin of a PC sheet printer a digital frank
Franking
Franking are any and all devices or markings such as postage stamps , printed or stamped impressions, codings, labels, manuscript writings , and/or any other authorized form of markings affixed or applied to mails to qualify them to be postally serviced.-Franking types and...

or stamp delivered via the Internet. With this innovative alternative to an adhesive-backed postage stamp
Postage stamp
A postage stamp is a small piece of paper that is purchased and displayed on an item of mail as evidence of payment of postage. Typically, stamps are made from special paper, with a national designation and denomination on the face, and a gum adhesive on the reverse side...

as the basis for an Electronic Stamp Distribution (ESD) service, a business envelope could be produced in-house, addressed and customised with advertising information on the face, and ready to be mailed.

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 equipments such as franking and addressing machines. They are all four symbiotic: technological developments affecting one obviously 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. For example, the advent and adoption 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 equipments were effectively rendered obsolescent and resulted in a flurry of lawsuits involving Pitney Bowes among others. The advent of e-mail
E-mail
Electronic mail, commonly known as email or e-mail, is a method of exchanging digital messages from an author to one or more recipients. Modern email operates across the Internet or other computer networks. Some early email systems required that the author and the recipient both be online at the...

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 replacement by 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.

Although as regards e-mail developments there is a substantial threat of "technology replacing tradition", this is offset by the equal reasoning that the Universal Postal Union
Universal Postal Union
The Universal Postal Union is an international organization that coordinates postal policies among member nations, in addition to the worldwide postal system. The UPU contains four bodies consisting of the Congress, the Council of Administration , the Postal Operations Council and the...

is an international
International
----International mostly means something that involves more than one country. The term international as a word means involvement of, interaction between or encompassing more than one nation, or generally beyond national boundaries...

specialised agency of the United Nations
United Nations
The United Nations is an international organization whose stated aims are facilitating cooperation in international law, international security, economic development, social progress, human rights, and achievement of world peace...

, and a source of revenue for government
Government
Government refers to the legislators, administrators, and arbitrators in the administrative bureaucracy who control a state at a given time, and to the system of government by which they are organized...

. Consequently any deterioration of domestic and international postal services attended by loss of revenue is a matter of governmental concern.

## Mailers

Some envelopes are available for full size documents. The Postal Service and Express mail
Express mail
In most postal systems express mail refers to an accelerated delivery service for which the customer pays a surcharge and receives faster delivery. Express mail is a service for domestic mail and is governed by a country's own postal administration...

carriers have large mailing envelopes for their express services. Other similar envelopes are available at stationary supply locations.

These mailers usually have an opening on an end with a flap that can be attached by gummed adhesive, integral pressure sensitive adhesive

Adhesive tape is one of many varieties of backing materials coated with an adhesive. Several types of adhesives can be used.-Types:Pressure sensitive tape...

.
Construction is usually:
• Paperboard
Paperboard
Paperboard is a thick paper based material. While there is no rigid differentiation between paper and paperboard, paperboard is generally thicker than paper. According to ISO standards, paperboard is a paper with a basis weight above 224 g/m2, but there are exceptions. Paperboard can be single...

• Corrugated fiberboard
• Polyethylene
Polyethylene
Polyethylene or polythene is the most widely used plastic, with an annual production of approximately 80 million metric tons...

, often a coextrusion
• Nonwoven fabric

Shipping envelopes can have padding to provide stiffness and some degree of cushioning
Cushioning
Package cushioning is used to help protect fragile items during shipment. It is common for a transport package to be dropped, kicked, and impacted: These events may produce potentially damaging shocks. Transportation vibration from conveyors, trucks, railroads, or aircraft can also damage some...

. The padding can be ground newsprint
Newsprint
Newsprint is a low-cost, non-archival paper most commonly used to print newspapers, and other publications and advertising material. It usually has an off-white cast and distinctive feel. It is designed for use in printing presses that employ a long web of paper rather than individual sheets of...

, plastic foam sheets, or air filled bubbles.

• Back-of-the-envelope calculation
Back-of-the-envelope calculation
A back-of-the-envelope calculation is a rough calculation, typically jotted down on any available scrap of paper such as the actual back of an envelope...

• Mail Art
Mail art
Mail art is a worldwide cultural movement that began in the early 1960s and involves sending visual art through the international postal system. Mail Art is also known as Postal Art or Correspondence Art...

• Packaging
• ✉ Envelope character in the Dingbat
Dingbat
A dingbat is an ornament, character or spacer used in typesetting, sometimes more formally known as a "printer's ornament" or "printer's character"....

s section of Unicode
Unicode
Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...

• Paper size
Paper size
Many paper size standards conventions have existed at different times and in different countries. Today there is one widespread international ISO standard and a localised standard used in North America . The paper sizes affect writing paper, stationery, cards, and some printed documents...