With the release of the 10c stamp portraying General Joseph ‘Vinegar Joe’ Stilwell on 24 August, the USA has embarked on a new definitive set which will be known as the Distinguished American series. This brings to an end the Great Americans series which has been on the go for the past twenty years. The Transportation coil series is continuing for the time being, featuring everything from an Indian canoe to an Otis elevator and every conceivable form of wheeled vehicle for good measure. Elsewhere, Germany is persevering with the Famous Women sheet stamps, introduced in 1986, and the Landmarks coil and booklet stamps, pioneered in 1987. These definitives have the virtue of freshness and variety, with a wealth of material of thematic interest.

Meanwhile Britain soldiers on with the Machin series which first saw the light of day back in 1967. Arnold Machin’s plaster effigy of the Queen, photographed on a plain background, has remained constant, even if the currency has changed, and the Machins now hold the record, if not for longevity (still held by Norway’s posthorns of 1872, with Denmark’s numeral series of 1933 lagging well behind) then certainly for the number of different stamps by denomination and colour. Even on a fairly simplified basis, a straightforward collection of the different Machins from the halfpenny to £5 is a truly mind-boggling sight, now running to well over 200 stamps. Several denominations have appeared at various times in at least three different colours; the 18p first appeared in deep violet in 1981, then re-emerged in deep olive-grey in 1984 and latterly was released in bright green in 1991. The 20p has been dull purple (1976), turquoise-green (1988) and brownish-black (1989) while the 5p has been pale violet (1971), claret (1986) or dull red-brown (1988). By contrast, the 1p stamp is listed in the catalogues as crimson, but the range of shades is quite remarkable.

However, when you take into consideration the subtle minutiae caused by six different printers (Harrison, Questa, Waddington, Walsall, Ensched_ and De La Rue), perforation (including the addition of elliptical perfs at the sides), PVA or PVAD gum, phosphor bands of various widths, colours and radiation, phosphorised or ordinary paper, the intricacies of ACP or FCP coated papers and blue fluor, you can begin to appreciate that there’s more to the Machins than meets the eye!

Then there the differences created by the printing processes, first photogravure, then lithography and most recently intaglio used for the current high values; but don’t overlook the large-format Machins which were in use in 1977-87 mainly as parcel high-values. Originally photogravure, they were revived recently for a prestige booklet of first class stamps printed in letterpress or albino embossing as well as the more usual processes. Coils, especially the mixed value strips which used to appear in vending machines and later were much favoured by the Reader’s Digest, add another dimension to the study, while booklets and booklet panes are a vast subject, a lifetime’s study in their own right. At the beginning of the Machin period booklets were still stitched, but later came the Swedish style booklets, then ‘window’ and barcode booklets, and finally the range of prestige booklets with their mixed panes yielding numerous ‘one-off’ varieties and se-tenant combinations as well as permutations of phosphor banding.

At first the Non Value Indicator (NVI) stamps only occurred in booklets, complicated enough by the fact that the contract was shared between Harrison, Questa and Walsall, but latterly they have also been released in sheets. Then there was the short-lived experiment with the ‘landscape’ format self-adhesive stamps, confined to the Tyne-Tees television area, followed by self-adhesive stamps in the upright ‘portrait’ format. There are subtleties such as the pointed and blunt bust types and the Jeffery Matthews reworking of the numerals of value. Then there are the myriad plate flaws, constant varieties and retouches, not to mention imperforate and partially perforated stamps and other errors which add spice to any collection. And we haven’t even considered the regional or ‘country’ versions which since 1971 have notched up a formidable array of stamps from Scotland, Wales, Northern Ireland and (till 1973) the Isle of Man.

Anyone still doubting that the Machin decimal stamps, now in their 30th year, are the most complex stamps of all time, should consult the ninth edition of the Stanley Gibbons Specialised Catalogue, volume 4 which, confined to the decimal definitives, now runs to almost 900 pages. Even the so-called Millennium first class definitive, introduced earlier this year, yields three distinct types so far. The Machin series clearly has a lot of life in it still, with the constant appearance of new varieties to keep the serious student on his or her toes.