Test Stamps

A test stamp, dummy stamp, or training stamp, is a label resembling a postage stamp that is used by postal authorities for testing equipment and/or training postal workers. They generally have the same size and shape as regular stamps, but with a minimal design. Although not normally made available to the general public, some are in private hands, and it is a recognized stamp collecting specialty.In the United Kingdom test stamps for coil dispensing machines are sometimes known as poached eggs, because of their design. They are printed the same size and format as the definitives and perforated in the same manner. The amount of ink used is also the same as actual postage stamps, so that they can be used to test the machines with material as close as possible to the actual postage stamps. The colour of these test stamps was changed from green to black after 1937 when some test coils were accidentally left in a machine and used as half-penny stamps. At the time of this colour change, text was also added to the centre of the labels indicating their use.In Germany test stamps were used between 1915 and 1930 to show advertisers in stamp booklets what their advertisement would look like. Small series of booklets were produced with large coloured numbers instead of the stamps for this purpose. These booklets are now very rare.

Postage Stamp Gum

In philately, gum is the substance applied to the back of a postage stamp to enable it to adhere to a letter or other mailed item. The term is generic, and applies both to traditional types such as gum arabic and to synthetic modern formulations.
The use of gum was part of the original proposal by Rowland Hill, and has been universal from the beginning. There have been a number of stamp types that were issued ungummed, typically due to emergency situations when gum was not available, such as Italy in 1944, Kraków issue of Poland in 1919, Latvia in 1919. Other reasons have included lack of access to gum (the typewritten "Cowries" of 1895 Uganda), extreme tropical climate (1873 Curaçao and Suriname), and intent to sell only to collectors (as with the US "Farley's Follies" souvenir sheets of 1933). The manual gluing-on of postage is such an extreme consumption of time (and "time is money" to businesses with a lot of mail) that these situations are always temporary.
Originally, gumming took place after printing and before perforation, usually because the paper had to be damp for printing to work well, but in modern times most stamp printing is done dry on pregummed paper. There have been a couple of historical instances where stamps were regummed after being perforated, but these were unusual situations.
On early issues, gum was applied by hand, using a brush or roller, but in 1880 De La Rue came up with a machine gumming process using a printing press, and gum is now always applied by machine. The gum is universally spread as uniformly as possible, but a 1946 local issue by the town of Finsterwalde in Germany used an economy process where the back of the stamp had a regular pattern of circular bare patches.
The greatest manufacturing problem of the gumming process is its tendency to make the stamps curl, due to the different reaction of paper and gum to varying moisture levels. In the most extreme cases, the stamp will spontaneously roll up into a small tube. Various schemes have been tried, but the problem persists to this day. In Swiss stamps of the 1930s, Courvoisier used a gum-breaking machine that pressed a pattern of small squares into the gum, resulting in so-called grilled gum. Another scheme has been to slice the gum with knives after it has been applied. In some cases the gum solves the problem itself by becoming "crackly" when it dries.

Semi-postal design

A semi-postal stamp or semipostal stamp is a postage stamp issued to raise money for some purpose (such as a charitable cause) and thus sold over and above the cost of postage. Typically the stamp shows two denominations separated by a plus sign, but in many cases the only denomination shown is for the postage rate, and the postal customer simply pays the higher price when purchasing the stamps.

The first semi-postal was actually a postal card; to commemorate the Uniform Penny Post in 1890, the United Kingdom issued a card with a face value of one penny, but sold it for sixpence, with the difference given to a fund for postal workers. The first semi-postal stamps were issued by the Australian colonies of New South Wales and Victoria, who both marked the Diamond Jubilee of Queen Victoria in 1897 with stamps denominated in pennies, but sold for shillings, a 12x increase over the face value.

Semi-postals became widespread in European countries at the beginning of the 20th century. In many cases they have become standard annual issues, such as the pro juventute series of Switzerland started in 1913. Many countries issued semi-postal stamps to raise money for the Red Cross in World War I. The surcharges are typically a fraction of the face value; at one points the Fédération Internationale de Philatélie was officially boycotting stamps with surcharges greater than 50 percent of face value, saying that such issues were exploitive of stamp collectors.

By contrast, the United States is a relative newcomer to semi-postals, with its first semi-postal being the breast cancer research stamp issued in July 1998. Several more have been issued since then.