From around 1850 until 1910, most postage stamps in Britain were manufactured using surface printing techniques. In some cases, however, two stamps that look alike to the casual observer can turn out to be distinguishable because some stamps during the period were printed by gravure. It is necessary, therefore, to be able to identify one from the other in order to properly evaluate an individual specimen.
One thing that might confuse someone new to stamp collecting comes from the word "issue", which might raise the expectation that the topic in question is about flaws discovered in the printing process that might make a stamp valuable. "Issue" is used in this context to mean something akin to publication. An issue of a stamp is like an edition of a book. Editions might in most respects be identical, but small differences can be introduced, and for stamp manufacture, a change of process is one of them. To grasp the significance of surface-printed issues in relation to stamp production then, some knowledge of printing processes and the history of their use is necessary before the collector can confidently set about identifying individual examples.
To begin with, determining whether a stamp has surface-printed issues requires some knowledge of the various printing technologies that have been used over the years. In the present day, new variants are constantly being invented, and it can be confusing to keep track of them all. However, the surface printing method is not common nowadays, if it is used at all, so a historical perspective is also valuable. There are four main techniques: offset litho, engraving, embossing, and surface printing. There are also a number of variant names to be aware of.
The most commonly used method used to print modern issues is offset litho. With this method, a plate is engraved with the image that is to be printed; usually, there are several plates, one for each colour of ink. Ink and water are then applied to the plate: ink sticks to the image, while water sticks to the rest of the form. The plate prints onto a rubber sheet, which in turn is printed on the paper. The original plate and the paper never meet, hence the term "offset".
Engraving, Intaglio, or Gravure
Before the offset litho process was invented, engraved plates were applied directly to the paper. In this process, the plate receives its image by a process that creates recesses in its surface, either by the direct action of a craftsman or else by chemical means, such as etching with acid. Once created, the plate is inked and then its surface is wiped clean, leaving ink in the recesses. It is then pressed onto the paper at high pressure. This can leave a characteristic mark on the paper, the inverse of embossing with the inked area subtly raised by comparison to non-inked areas. Something that philatelists look for is the difference between issues printed on flat presses as compared to cylindrical presses, with the latter tending to be slightly longer than the former in proportion to the width.
Embossing is rarely used in stamp-making, but it has been used for special issues marking special events. Briefly, the effect is to raise the desired image above the plane of the paper. The technique can, and usually is, used in conjunction with one of the other methods.
Surface Printing, Relief, or Letterpress
Surface printing, then, is the oldest printing technology used in stamp production. Essentially it is a sophisticated version of potato printing, and incidentally, it is also the method used for hand-franking and rubber stamps in general. The non-printing areas of the form are removed, leaving the image raised to receive the ink. There are a number of terms for this process other than surface printing: relief, letterpress, and typography. This latter term, "typography", is a historical inheritance sometimes used by philatelists, but it is confusing to the modern eye because it also applies to the craft of print design generally.
The most recognisable characteristic of surface printed stamps is a tendency for the image to be uneven. The effect of pressing the image to the paper is that the ink is squeezed and as a result tends to flow to the edge of the impression, leaving a halo of greater density around the edges of the printed areas.
Printing History and the Postage Stamp
Throughout the history of postage stamps, there have been competing demands for, on the one hand, keeping costs to a minimum, and on the other, inscribing security features to prevent fraud. In its heyday, letterpress was better suited to the former consideration, so for several decades in the Victorian era and after, most low-value stamps were made this way. The first stamp though, the penny black, was initially engraved. Letterpress arrived a few years later, with the invention of perforation.
By the late nineteenth century, postage stamps were being used in ways traditionally associated with more specialised financial transactions, and values as high as £5 was manufactured. It was discovered that forgers had been operating for some twenty years, and changes in production methods were rapidly introduced. Some of these forgeries can still be found in the market as low-priced curiosities. Below is a chart that summarizes the printing technology and when it was used.
1840 on; little used now
1850 to 1910 approximately
The table shows the relationship between time and technology in stamp printing. Offset and litho techniques were invented and used for various reasons earlier than the 1930s, but as a simple rule of thumb, letterpress and offset litho do not overlap.
With all that background knowledge in place, the collector can set about identifying stamps by the technology used in their manufacture. By comparison with some of the other aspects of printing technique that collectors pay attention to, such as watermarks and phosphors, very little equipment is needed, just some basic tools and a useful book or two.
Since care and caution are strongly advised when handling valuable items, some light cotton gloves can be a worthwhile purchase. Then, for close examination of an individual stamp, use a pair of tweezers and a magnifying glass. With these items to hand, use the pointers already discussed to determine whether an individual stamp is from a surface printed issue.
A general catalogue such as the Stanley Gibbons is a good place to start. After that, there are books dedicated specifically to surface printed issues. However, such books as "Great Britain Surface Printed Postage Stamps 1855-1883: Low values 2½d to 2s", published by the Great Britain Philatelic Society are seldom listed on eBay. There are older books too, such as the 1949 "British Postage Stamp Varieties Illustrated. Queen Victoria surface-printed issues to King George VI", which can become collectable items in their own right. Bear in mind that for people in the early stages of starting a collection, a local library often has stamp catalogues on its shelf.
Buying Surface Printed Stamps on eBay
Because surface printed stamps were issued in such high volume during the nineteenth century, they are easy to find on eBay simply by typing "surface printed" into the search window on the home page. Alongside the tabulated search results, you should find a series of filters that enable you to home in on the specific item you are looking for. Initially, these are likely to be fairly broad, so a series of filters can be progressively applied to reach, for example, Victorian era British surface printed issues. Note, however, that some filters supersede others. Since most surface printed issues were issued in Britain during the Victorian era, going straight to a printing method filter should mostly be populated with these.
The various selling categories offer listing options to the vendor, and it may be that as a result a stamp is displayed by a filter because the seller has chosen "surface printed", but the text of the advertisement makes no mention of the printing method. In these cases, if you are in any doubt about it, you can make contact with the seller to double-check before placing a bid.
The simplest answer to the question how to determine if a stamp has surface-printed issues is to look the item up in a catalogue. Any serious collector, however, may want to understand what lies behind the term and others with which it might be compared. Printing technology is a complicated field, one that is constantly evolving, and also one in which separate techniques already in use can come together to create a new one, as is the case with offset litho.
Nevertheless, one need not be blinded by science. Not only was surface printing the dominant technique for stamp production in Victorian Britain, but the successive issues are well documented, and there is a fund of expertise several generations deep to guide anyone new to the field. As well as consulting books, a buyer can contact anyone selling an item on eBay to gain further information when it is needed in the expectation of a helpful response, useful feedback, and ultimately a confident purchase.