Stamps are complex collectables, and vary greatly in their design, printing methods, perforations and varieties.
- Stamp Design
- Overprints and Surcharges
- Cinderella Stamps
No stamp is ever printed without a reason. It might be for a special occasion, such as the Olympic Games, or an anniversary of a famous event. Perhaps the postal rates are being changed and the stamp designs are altered at the same time.
The Stamps Business of NZ Post compiles each annual stamp programme establishing the number of stamps to be issued and the subjects to be depicted. Special anniversaries and events are all considered when deciding what stamps to issue. Many organisations also write to NZ Post suggesting events or subjects that would be good on a stamp and all of these are considered carefully.
Once the subject of the stamp issue has been decided, a number of designers are invited to develop concepts. The best concept is chosen to be developed through to finished art and the designer sets to work to complete the final design. Often, there will be a number of changes to make to the initial design before it is finally accepted.
Once the final design has been approved, it is sent to the printer. The stamp design is copied many times so that lots of stamps can be printed on one sheet of paper.
Three methods of stamp production are currently employed to produce NZ Postage stamps:
This method is also described as 'recess' or 'engraved'. It was by this process that the first postage stamps in England in 1840 were produced.
There are distinct stages in the preparation of a printing plate for Intaglio printing:
- The original die is prepared from a small plate of high quality steel. in order for the engraver to work upon the steel, it is submitted to a process of decarbonisation by which it is softened. The design is applied in reverse and colour lines in recess. These days the actual engraved image can be applied by photographic and chemical means to the metal plate (at much less cost) but this process results in lines all of a similar depth and cannot achieve the subtleness of the hand engraved image.
- Once the image is engraved the die is hardened and a "transfer roller" is produced. This is a circular piece of metal which is softened by the decarbonisation process and which is rolled over the hardened die under great pressure in a transfer press. Consequently the soft metal is forced into the grooves cut by the die. The roller is then ready for making the printing plate. The impression on the roller is positive, that is, exactly as the stamp will be printed.
- As with the die and the roller, the sheet of steel from which the printing plate will be made must be softened to take the impression of the roller. Under considerable pressure the roller is applied to the plate the desired number of times. The plate is then hardened and printing may commence.
- During the printing process ink is applied to the plate followed by a sheet of stamp paper which then moves under a roller exerting considerable pressure with the result that the paper is forced into the grooves cut in the plate and picks out the ink therein. A particular feature of this method in printing is that the ink on the paper stands above the paper surface and may be identified by touch.
This is a modern method of printing which dates back to 1798. The original process consisted of transferring a design to a stone with special greasy ink. The flat printing surface was then moistened so that when the ink was applied it only adhered to the greased portion and this was then impressed onto paper without the use of any real pressure.
In offset-lithography the image is photographed by means of a step and repeat machine onto a specially sensitised sheet of thin zinc. The image on the plate is inked and transferred "offset" by a rubber sheet or blanket on to the stamp paper.
In the more modern version of photo-lithography the stamp design is photographically processed onto an etched zinc plate which is then attached to the cylinder of a rotary printing press.
Photogravure is a form of recess printing. The basic design is photographed and the negative is used as a master die from which a series of positive images, as required to make up a sheet of stamps, are produced on a glass plate. This plate is known as the "multipositive". The plate is processed onto a carbon tissue which has a "screened" surface of finely crossed lines. The carbon tissue is then wrapped around a copper cylinder and etched with a solution of ferric chloride, leaving a pattern of small recesses on the cylinder. These correspond to the "grid" formation of the screen and vary in depth according to the strength of the tones on the multipositive plate. The cylinder is then chrome-plated and used for printing.
While being a complicated process it is also one that is more suited to large production runs, making it uneconomical for small orders when compared to photo-lithography.
Just like banknotes, many stamps used to be printed on watermarked paper, so that if you hold the stamp up to the light the watermark will show up.
On some stamps the watermark is hard to see, so expert collectors use a watermark detector. This is usually a black tray or a tile with a polished surface. The stamp is placed face downwards on the tray and the watermark usually shows up quite clearly.
All sorts of watermarks have been used on stamps, including lotus flowers, lions, pineapples, castles, an umbrella, a conch shell, an elephant's head, a pyramid, a honeycomb, turtles, roses, shamrocks, thistles, and aeroplanes. Even the common crown watermark varies. For instance, English stamps have featured both a Tudor crown and a St. Edward's crown. In the case of New Zealand’s early stamps the letters NZ and a star were a common watermark
The perforation on a stamp is the row of holes along which the stamps are ripped to separate them from each other. The gauge of a perforation is determined by the number of holes along a 2 centimetre line. A wide range of perforation gauges has been used in the production of New Zealand stamps.
The very first stamps that were issued were imperforate (not perforated) simply because nobody had invented a machine for making perforation holes at that time. To separate the stamps, they were cut with scissors and, often, not very carefully. That is why many very old stamps are found with cuts in them or with borders missing.
A machine to perforate stamps was invented by Henry Archer, an Irishman, about 1847. He wrote to the British Postmaster General saying that it would be better if all stamps were perforated. The Postmaster General liked the idea and, in 1854, the world's first perforated stamps were officially issued by Great Britain.
The perforations can also make a difference to the value of the stamps. Sometimes the number of 'holes' in the perforation can be different on the same stamp design and make one stamp of the same design more valuable than the other. This happened to a New Zealand stamp issued during the World War II. These stamps are known as Blitz Perfs and were printed by one firm and perforated by another because the first firm was bombed and lost part of its machinery. So one issue of these stamps had 13½ perforations down its side while the other had 14 perforations. The stamp with the 14 perforations is the Blitz Perf and is very valuable.
Some stamps come with two sides perforated and two imperforate. These are known as 'coils' because they were made in a long strip for use in stamp machines. Others may have only three sides perforated. these being stamps produced in a booklet format and have been guillotined down one side when the booklets were being produced.
Gum on the back of a stamp is important to a collector as it makes the stamp closer to perfect condition.
Gum is applied to the back of stamp paper before the stamp design is printed on it. The gum used on many early stamps contained a substance called dextrin or potato starch. The gum was usually a white colour but not always. In 1855 the backs of some British stamps were coated with green gum, while the German state of Hanover used red gum on its stamps as early as 1850. Today, an almost invisible gum called PVA gum is used on most stamps.
One problem of coating paper with gum is that the gum causes the paper to curl up and makes it hard to print the stamp design on it. So, once the paper is covered with gum, the paper goes through a special machine that causes the gum on the paper to crack up into little pieces. This stops the paper from curling up.
Surcharges are where the value of the stamp has been changed by having another value printed on the stamp, usually in black. For example, a 2½ cent New Zealand stamp featuring the Magpie moth, had two lines printed through the 2½ cent value on the stamp and a 4 cent surcharge value printed at the top of the stamp.
Overprints are things added to a stamp after it has been printed. For example, a New Zealand ½d stamp issued during World War I had the words 'War Stamp' overprinted on it. Another stamp, issued in 1940 to mark the centennial of New Zealand, was overprinted with the word 'Official'. A stamp overprinted with this was used on official business by a Government office.
Because it is easy to forge overprinted or surcharged stamps, surcharges and overprints usually lower the value of the stamp. However, as overprinting and surcharging is usually done in a great hurry and often by local printing companies, some odd things happen to surcharged or overprinted stamps - letters are missing or upside down, or stamps are surcharged twice on the same stamp. Where this has happened and the surcharging or overprinting is not forged, the stamp is likely to be very valuable.
'Varieties' is the name given to stamps that are different in some way from the normal issue. This can be because of a mistake in the stamp's design, printing, overprinting, colour, paper, perforation, or watermark.
Often the mistake is simply a printing fault such as a missing dot or part of the stamp that has not printed properly. On some stamps, though, there have been mistakes made when the stamp was designed. For example, on one Swiss stamp there was a picture of William Tell's son holding an arrow and an apple, standing behind his father's bow. When the stamp was first issued, the stamp designer had drawn the bowstring 'in front' of the cross-bow stock. When this mistake was discovered, the stamp was re-issued with the bowstring 'behind' the cross-bow. This makes this stamp quite valuable and very popular amongst expert stamp collectors.
Sometimes there are differences in the colours of the stamps as a result of a printing fault. However, as it is difficult to tell whether a stamp is a different colour because of a printing fault or simply because the stamp has faded over time.
Cinderella stamps are not valid for postage, however many of these stamps are very interesting.
There are many types of Cinderella stamps - Local Posts, Fiscal Stamps, Railway, Newspaper and Delivery stamps; Exhibition and Commemorative Labels, and Charity seals.
Some of the most famous New Zealand Cinderella stamps are the Pigeon Post stamps. These were used on letters carried by pigeons between Great Barrier Island and Auckland during the years 1898 and 1904. The Pigeon Post was started after the steam ship Wairarapa, on October 29, 1894, steamed at full speed into 800ft high cliffs on Great Barrier Island killing 135 people. This showed that there was a need for a fast message service between the island and the New Zealand mainland. The first messages sent by Pigeon Post were sent on very light rice paper and cost 2/- each to send.
Other famous New Zealand Cinderella stamps are the Reefton Provisional stamps, Beer Duty stamps, Wage Tax stamps, and Fiscal Stamps.