A guide to stamp condition and value: gum (part 1)

British Guiana

A guide to Stanley Gibbons’ definition of ‘fine’

The quality and overall condition of a stamp are vital when determining its value and each feature of a stamp has to be considered. The state of the gum on the reverse, the condition of the margins and perforations and whether it has faded or sustained damage are just some of the factors that can have a dramatic impact. The article below covers the subject in great detail and is essential reading.

What exactly does ‘fine’ mean and how do slight defects affect the price? To quote in full the relevant paragraph in the introduction to the current Stanley Gibbons Commonwealth and British Empire Stamps Catalogue; ‘The prices quoted in this catalogue are the estimated selling prices of Stanley Gibbons Ltd at the time of publication. They are, unless it is specifically stated otherwise, for examples in fine condition for the issue concerned. Superb examples are worth more, those of a lower quality, considerably less.’ This single paragraph is probably the most significant piece of information in the entire catalogue – but one that is frequently ignored or forgotten. The big question, of course, is just how much more is ‘more’ and how much less is ‘less’?

Not surprisingly, the ability to answer that question depends on experience.  A knowledgeable philatelist will be able to assess fairly quickly what the price of a particular stamp should be in relation to that quoted in the catalogue. Many sellers, however, both professional and collector, find it simpler to price items for sale by a standard percentage of ‘catalogue’; probably only marking down those that are actually damaged. This can mean that stamps in better than ‘fine’ condition are underpriced, while poorer ones are too expensive; something which buyers need to bear in mind.

Talking to the experts, it quickly becomes obvious that every single feature of a stamp needs to be considered separately before a judgement on its overall condition can be passed. So this article will look at each of those features individually, before drawing them all together and attempting to assess how much more than catalogue price a superb example might be worth and, conversely, how low a price should be put on one of lower quality.


This would seem to be a relatively easy one – after all it says in the catalogue;  ‘The prices for unused stamps of Queen Victoria to King George V are for lightly hinged examples. Unused prices for King Edward VIII to Queen Elizabeth issues are for unmounted mint.’ Well, at least the definition of unmounted is pretty clear, while lightly hinged means, in theory, a single hinge mark, although, apparently, two or three might be acceptable if the hinges have been lightly applied and carefully removed.

The stamps printed by De La Rue for the majority of Colonial postal administrations during the first three decades of the twentieth century have stood up reasonably well to stamp hinges, so finding lightly mounted examples of such stamps should not be too difficult. However, Canadian stamps, for example, which were printed on softer paper and had thicker gum, are more difficult to find in fine mounted condition and should be valued accordingly.

British Guiana

Heavier hinging is acceptable for stamps issued before around 1890 but the majority of the gum should be clear and ‘unblemished’. If the stamp has been mounted on a number of occasions or if there is a heavy hinge still attached, the price would drop to about half catalogue and from there on would decline fairly rapidly.

For a twentieth century stamp without gum a price of about one tenth of catalogue would be more or less the order of the day (unless it was normally issued that way, of course!). However, many early issues are extremely rare with gum and in these cases anything up to full catalogue price would be appropriate.  Prices for early Western Australia and Sarawak are, for example, without gum; gummed stamps being worth a premium.

The first perforated issues of British Guiana are also rarely found with gum, so ungummed examples would be worth a higher proportion of catalogue price than usual – about one third, or more – while Turks Islands provisionals and early New Zealand Chalon heads without gum might rate half catalogue or above.

As for the premium that should be put on earlier stamps in unmounted condition, that will vary from issue to issue and from country to country. Clearly, the older the stamp the less likely it is that it will be easy to find by those seeking ‘unmounted’ perfection. The Great Britain Concise catalogue gives both mounted and unmounted prices for all stamps issued between 1887 and 1935 and the premium ranges from zero, up to 100 per cent, or even more, depending on the relative scarcity of the stamp in unmounted condition.

Even for King George VI stamps the discount for mounted mint can vary as suggested earlier, Commonwealth collectors are fortunate in that the price differential is not nearly so dramatic. On average, mounted mint prices for post-war King George VI sets are approximately ‘half catalogue’. Again, there are exceptions: to take three examples; the first King George VI 3d. of Ascension, the black and ultramarine stamp (42), would only rate around 25 per cent of catalogue in mounted condition, on the other hand, the 1938 set of Perak (103/21) would be more like two thirds, while for some of the Indian Convention States high values the proportion would be even higher. For the first issues of the present reign the proportion drops to around a third, but after about 1965 there is really very little demand for mounted examples of anything other than the more expensive sets, even in fine lightly hinged condition.

Whether or not a hinge has been attached to it is not the only gum feature that can affect the value of a stamp. Discoloration or toning can also be significant. Stamps which have spent time in the tropics frequently suffer from gum browning and, in extreme cases, cracking and ‘crazing’, sometimes affecting the face of the stamp as well as the back. The value of such specimens should be marked down accordingly.

For stamps of King George VI one would normally aim for no gum toning at all, but the first 10s. definitive of Grenada only exists toned, so that would be considered ‘fine for the issue concerned’; later stamps in the series should have cream or white gum, depending on the original issue.  Again, the vast majority of the first Hong Kong definitives have at least some gum toning, so here the discount for lightly toned examples would be smaller than usual.

The demand for unmounted mint, as well as very real concerns that the gum applied to nineteenth century issues was, in itself, potentially damaging, has inevitably led to a certain amount of regumming.  Stanley Gibbons’ policy is not to sell stamps which have been regummed, especially since the new layer of gum may disguise damage or attempts at repair. It is important, therefore, that the edges of early mint stamps be checked very carefully to make sure that there are no suspicious signs of gum on the surface. (There is one set of stamps, China SG 457/9, which was gummed after printing and perforating, while stamps printed on top of the gum are clearly not a problem – but these are very much the exceptions.)

This guide is part of a series of 5 guides: “A guide to stamp condition and value”. The entire series can be found here:

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