Envelope
Traditional envelopes are made from sheets of paper cut to one of three shapes: a rhombus, a short-arm cross or a kite.
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.
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.
[citation needed] 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 "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.
[4] 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).
During the U.S. Civil War those in the Confederate States Army occasionally used envelopes made from wallpaper, due to financial hardship.
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.
As envelopes are made of paper, they are intrinsically amenable to embellishment with additional graphics and text over and above the necessary postal markings.
In the Southern Song dynasty, the Chinese imperial court used paper envelopes to distribute monetary gifts to government officials.
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.
)[citation needed] Nearly 50 years passed before a commercially successful machine for producing pre-gummed envelopes, like those in use today, appeared.
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 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] Their use first became widespread in the UK when the British government took monopoly control of postal services and tasked 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.
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.
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.
[citation needed] 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.
[citation needed] 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.
