But although the paper from which these first machine-made envelopes were made was cut to the shape of a rhombus or diamond and creased ready for folding to form a rectangular enclosure, it did not have the edges of the overlapping flaps treated with a paste or adhesive. The method of securing the envelope or wrapper was a user choice.
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 it is undeniably a paper-efficient way of producing a rectangular-faced envelope and was in use at the beginning of the 19th century before Hill and De La Rue's machine appeared.
The most famous paper-making machine was patented by the Frenchman Fourdrinier in 1799. The process involves taking processed pulp stock and converting it to a continuous web which is gathered as a reel. Subsequently the reel is converted to a large number of properly rectangular sheets by guillotining across it reel edge to edge.
The rectangle is a geometric form which occurs infrequently,perhaps never, in nature, but has been long and widely used by mankind in the shaping of materials. By producing machine-made paper as properly rectangular sheets they are intrinsically compatible with printing and duplicating machines - which have always been primarily designed to process flat rectangular sheets, beginning with the Gutenberg press.
Consequently, when mechanically reproducing graphics or text on an envelope the approach best compatible with printing technology is to print on the flat and then cut to shape, crease, gum and fold.
However, reproducing an item using a mechanical process always incurs costs relating solely to the machinery itself. These are "absorbed" by making as many or as much of the item as is necessary to reduce the per-unit cost to an level considered acceptable by the customer.
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 and Dunnebier, producing two-thirds of the machines producing the 450 billion envelopes referred to above.
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 envelope 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 there is seldom the justification for this added expense. Furthermore the digital printing revolution which began in the late-20th century saw the introduction of an option for small businesses to overprint on the face of machine-made envelope themselves using their own PC sheet printers in association with suitable software.
And in 1998 the U.S. Postal Service approved the introduction of a system of applying to an envelope in the printer bin of a PC sheet printer a digital frank or stamp delivered via the Internet. With this innovation a business envelope could be produced in-house addressed, customised with advertising information, and ready tobe mailed.
The fortunes of the commercial envelope manufacturing industry and the postal service go hand in hand. And the advent of e-mail in the late 1990s appeared to offer a substantial threat to the postal service.
However the worldwide demand for envelopes continues to rise, and the Universal Postal Union, which is an international cartel of national postal administrations and a specialized agency of the United Nations, is unlikely to disappear overnight. Not least because the postal service is a dependable source of revenue for a government.Among the first five contracts awarded to American companies for the reconstruction of the social and economic infrastructure of Iraq was one of $55 million for a study of the postal system.