On May 29, 1997, I entered the Moscone Center in San Francisco, California, on the opening day of the massive PACIFIC 97 World Philatelic Exhibition. To date, this is still the only international (or, even national) stamp event that I’ve participated in. To say the least, I was extremely impressed and overwhelmed by what was the largest stamp show to be held in the United States that decade (the first one ever on the West Coast) and I have many fond memories of the two weeks I spent there. This was the absolute peak of my philatelic life!
I had flown to San Francisco the day before from my then-home in Albuquerque, New Mexico. For the duration of the show, I stayed with my aunt and uncle at their home in Walnut Creek on the opposite side of San Francisco Bay. Each morning, I would take the BART train into the city and spend most of the morning at the Moscone Center. My afternoons were usually spent sightseeing in my favorite city of the United States. One afternoon, I unexpectedly ran into my sister and brother-in-law on Fisherman’s Wharf. I had no idea they were vacationing there as well, having come in from Kansas City.
The numbers are impressive: there were 3,584 competitive frames exhibited as well as another 100 in the Court of Honor and 15 frames devoted to special exhibits. This computes to around 60,000 stamp album pages of material to look at. The total length of the rows of frames was just under two-and-a-half miles! Fifty-seven different countries were represented by these exhibits with particular emphasis on Pacific Rim participants. George Kramer won the Grand Prix National with “Across the Continent — Mail across the American Continent before the Completion of the Transcontinental Railroad in 1869,” which included the greatest Pony Express rarities. It was the first time a U.S. postal history exhibit had earned that honor. Two collectors from Thailand won the other top prizes: the Grand Prix International went to Pichai Burenasombate for “Classics of Great Britain,” and the Grand Prix d’Honneur went to Surajet Gongvatana for “Siam.”
More than 200 stamp dealers had booth and a number of philatelic auctioneers were in attendance (I sold my U.S. #1 and #2 as well as a Penny Black in one of the auctions). More than 130 different postal administrations were represented. My fondest memories are of visiting EVERY SINGLE ONE of the post office booths to buy at least one stamp (which was duly affixed into my philatelic passport and postmarked with each administration’s cancellation). I recall HUGE lines at the Hong Kong booth as the then-British colony was due to be handed-back to China the following month. The PACIFIC 97 Philatelic Passport is the item I most regret not bringing with me when I eventually moved to Thailand — an irreplaceable souvenir now lost forever.
Another highlight for me was the daily preparation of covers. The U.S. Postal Service released several stamps and postal stationery items at the exhibition. These included the first-ever triangular stamps released by the United States, a pair of souvenir sheets commemorating the 150th anniversary of the first U.S. stamps and featuring die proofs of the original designs, and two very attractive postal cards portraying the Golden Gate Bridge. The Franklin and Washington souvenir sheets created some controversy as they were only available for the duration of the show (the Washington sheet from May 30). Each day also had special USPS postmarks so it was quite fun preparing combination covers to receive the various cancellations available. I no longer have any of these (all remained in America when I made my cross-Pacific move), but I do remember making one or two very large covers that bore every available USPS cancellation (the first days and special days) that were available during the length of my stay.
There were a few interesting books published at PACIFIC 97 as well, including one about the Pan American Clippers. The 1997 edition of the American Philatelic Congress Book doubled as the PACIFIC 97 Handbook and contained many scholarly articles related to the themes of the show. There were many freebies on offer; Avery-Dennison distributed “dummy” self-adhesive stamp booklets and there were beautifully-engraved souvenir cards by the Bureau of Engraving and Printing available. It was also the first international stamp show to include a section for philatelic software.
Looking back, I feel that I was a rather unorganized collector. At PACIFIC 97, I felt like the proverbial kid in a candy shop — overwhelmed by the choices available. I like to believe that I’m much more organized in my present philatelic pursuits. I do long to attend another large stamp show. They seem to have one or two each year in Bangkok with a larger regional show every six or seven years. There are also shows in Malaysia and Singapore which are definitely within range (and budget!). The problem is finding details on these shows with enough advance notice to actually plan a trip! I often find out about the Thai exhibitions when there is a photo in the newspaper (usually of Her Royal Highness Princess Maha Chakri Sirindhorn opening the show). There must be a better way…
The slideshow below displays some items I’ve restored to my collection recently and a few I once had but now need to replace. When I came to southern Thailand more than 12 years ago, I never thought that I would stay so long. I was in one of those periods of “non-collecting” and never thought about picking up my tongs again. It wasn’t long before the philatelic bug bit me once again but, by then, it was too late as I’d instructed my sister to sell off the entire contents of my storage unit in New Mexico. The only items I requested her to “save” were certain music albums and a few books. If only….
We have quite the sticky subject today — that concerning all that is used to adhere stamps to covers or cards. The term ADHESIVE in philately can either refer to the gum on the back of a stamp, be it water-activated or self-adhesive, or the stamp itself affixed to prepay postage in contrast to a pre-printed design as on postal stationery. Stamps have also been issued without any adhesive at all and were affixed to envelopes by glue or other means.
It has been said that stamp gum, in its never-hinged state, is the most valuable substance on Earth.
The earliest human use of adhesive-like substances was approximately 200,000 years ago. Two stone flakes were discovered in central Italy partially covered with birch-bark tar and a third stone dating from the Middle Pleistocene era. This is thought to be the oldest discovered human use of tar-hafted stones.
The birch-bark-tar adhesive is a simple, one-component adhesive. Although sticky enough, plant-based adhesives are brittle and vulnerable to environmental conditions. The first use of compound adhesives was discovered in Sibudu, South Africa. Here, 70,000-year-old stone segments that were once inserted in axe hafts were discovered covered with an adhesive composed of plant gum and red ochre (natural iron oxide) as adding ochre to plant gum produces a stronger product and protects the gum from disintegrating under wet conditions. The ability to produce stronger adhesives allowed middle stone age humans to attach stone segments to sticks in greater variations, which led to the development of new tools.
The first references to adhesives in literature first appeared in approximately 2000 BCE. The Greeks and Romans made great contributions to the development of adhesives. In Europe, glue was not widely used until the period 1500–1700 CE. From then until the 1900s increases in adhesive use and discovery were relatively gradual. Only since the last century has the development of synthetic adhesives accelerated rapidly, and innovation in the field continues to the present.
In 1750, the first British glue patent was issued for fish glue. The following decades of the next century witnessed the manufacture of casein glues in German and Swiss factories. In 1876, the first US patent (number 183,024) was issued to the Ross brothers for the production of casein glue.
Before postage stamps existed, people receiving letters would have to pay for them. The payment was based on how many papers were in the envelope and how far the letter had traveled. Rowland Hill came up a solution of prepayment. At the time, he wrote that his prepaid postage adhesive would be “covered at the back with a glutinous wash.” This led to his invention of stamp gum in 1837; the first postage stamps used starch-based adhesives when issued in 1840.
The first U.S. patent (number 61,991) on dextrin (a starch derivative) adhesive was issued in 1867. Natural rubber-based sticky adhesives were first used on a backing by Henry Day (U.S. Patent 3,965) in 1845. Later, these kinds of adhesives were used in cloth backed surgical and electric tapes. By 1925, the pressure-sensitive tape industry was born. Today, sticky notes, Scotch tape, and other tapes are examples of PSA (pressure-sensitive adhesives).
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 pre-gummed 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.
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. On 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.
The appearance of the gum varies with the type and method of application, and may range from nearly invisible to dark brown globs. Types of gum used on stamps include:
• dextrin, produced by heating starch
• gum arabic or acacia gum, derived from the acacia plant
• glue, from gelatin, rarely seen on stamps
• polyvinyl alcohol
Some stamps have had gum applied in a pattern resembling a watermark, presumably as an additional security device. German stamps from 1921 had a pattern of wavy lines while Czech stamps from 1923 had gum showing the initials of the Czech Republic, CSP. These patterns have been called gum devices or gum watermarks.
A 1965 British study of the transmission of bacteria and viruses on gummed paper found that “Although pathogenic bacteria and viruses were not isolated from sample envelopes obtained from various sources, the gums used in manufacture were found to exert a protective effect against death from desiccation on the bacteria and viruses which had been introduced into them” and it was possible to demonstrate bacterial multiplication in the gum used for the manufacture of postage stamps.” The authors added the warning that “postage stamps are often handled very carelessly when issued over the counter, and yet the purchaser will usually lick them without hesitation. The present work shows how readily bacteria can adhere to the surface of gummed paper which has been slightly moistened; and the finger is a suitable source both of moisture and of bacterial contamination.”
A 1996 episode of the popular sitcom Seinfeld featured a character (Susan Ross) who was poisoned after licking the flap of too many gummed envelopes. The episode has been linked anecdotally to an increase in worries about the health risks of licking gummed paper and it has been speculated that it may have contributed to the growing popularity of self-adhesive stamps, at least in the United States.
For collectors, gum is mostly a problem. In 1906, trouble had constantly arisen due to the gum on the under face of the stamps. There was an official notice that stated that stamps were going to be prepared with ‘hard’ gum, and were intended for use in the summer or humid season to prevent the premature sticking together of the stamps, or the sticking to the paraffin paper when in book form. It is rarely of use in differentiating between common and rare stamps, and being on the back of the stamp it is not usually visible. Nevertheless, many collectors of unused stamps want copies that are mint, never hinged which means that the gum must be pristine and intact, and they will pay a premium for these.
While not so much of a problem for modern issues, the traditional way of mounting stamps in an album was with the use of stamp hinges, and some experts claim that very few unused stamps from the nineteenth century have not been hinged at some point in their existence. This means that old unused stamps are inevitably under suspicion of having been regummed, and the detection of regummed stamps is an important part of philatelic expertization.
The first self-adhesive stamps were issued by Sierra Leone in February 1964 and Tonga in April 1969 in an attempt to avoid the tendency of traditional water-activated stamps to stick together in humid conditions. They also made die cutting into fanciful and unique shapes easier.
Pressure-sensitive adhesives are manufactured with either a liquid carrier or in 100% solid form. Self-adhesives for stamps are made from liquid PSAs by coating the adhesive on a support and evaporating the organic solvent or water carrier, usually in a hot air dryer. The dry adhesive may be further heated to initiate a cross-linking reaction and increase molecular weight. 100% solid PSAs may be low viscosity polymers that are coated and then reacted with radiation to increase molecular weight and form the adhesive (radiation cured PSA); or they may be high-viscosity materials that are heated to reduce viscosity enough to allow coating, and then cooled to their final form (hot melt PSA, HMPSA). The stamps are usually issued on a removable backing paper.
The United States Postal Service’s first foray into self-adhesive stamps was in 1974 with the 10-cent Dove Weather Vane (Scott #1552), produced by Avery Dennison, that soon became discolored due to the instability of the adhesive. Another such stamp wouldn’t be issued by the United States until 1989. Stamp collectors criticized the format, as the rubber base adhesive used tended to progressively yellow the stamps. They also found them difficult to remove from covers, and to save in mint condition, though self-adhesives of recent years have improved in these respects.
The British Post Office first issued self-adhesive stamps on October 19, 1993, with the introduction of books of 20 First Class stamps, later a 2nd class stamp was introduced. In later years, other issues were produced in the self-adhesive format. Die cutting tools for the UK self-adhesive stamps were manufactured by Arden Dies of Stockport, Cheshire, using tools designed by Robert Clapham. Outside of the philatelic community, the stamps have been welcomed as more convenient; by 2002, virtually all new USPS stamps were issued as self-adhesives.
More recent USPS self-adhesive stamps are not readily removable from the envelope or cover backing by traditional water soaking. Some collectors of used stamps have discovered that although not readily removable by water, the self-adhesives can be removed with Bestine (a hexane solvent), Benzine (Petroleum Ether), or a natural based citrus solvent containing d-limonene (e.g., Pure Citrus Orange is an air freshener product that works for this purpose).
Many collectors are only interested in owning stamps in the pristine, mint, state in which they were originally sold at the post office. They are willing to pay a premium for stamps on which the gum has never been disturbed. For investment purposes there is nothing like the never hinged stamp with full gum.
Gum on stamps does have a number of disadvantages. It may crack, curl, become glazed and brittle, discolor, eat into the paper, attract vermin, stain and possibly harm the paper of the stamp itself, possibly even destroying the stamp over time. For this reason, there is a growing movement among collectors to abstain from the practice of collecting never-hinged stamp, even to the point of collecting stamps with no gum.
Other than mint stamps with full original gum, stamps are also described as lightly-hinged (LH) which show a slight mark where the stamp hinge was once attached. The gum is not greatly disturbed. Some stamps still have pieces of a stamp hinge adhering to its back which are described as having hinge remnants (HR). Heavily-hinged stamps may have been hinged badly or hinged more than once and may have a large area of missing gum and/or multiple hinge remnants.
Hinges may also turn brown with age causing discoloration to the stamps. Creases may occur in the gum due to careless handling. Thinned areas (“thins”) can also occur when removing hinges as the gum sticks to the hinge. Some gum is over-sensitive and can cause mint stamps to stick to each other if stacked prior to mounting in an album.
Gum used on some stamps contained sulfuric acid which destroy the paper over time and unused examples should be collected with the gum removed. Inferior gum used in the manufacture of stamps can result in damage when stamps are later subjected to less than ideal conditions, such as high heat and humidity.
Yes, gum is often the source of condition problems among stamps. It has been said that the long-range health and preservation of stamps would be better without gum. Short of soaking the gum from your stamps, the next best thing you can do is protect them by proper storage in albums or stock books and by not subjecting them to high humidity, sunlight or swings in temperature.