Historically, the 2d Queen-on-Throne is interesting insofar as it was the first stamp to be plated that was not trivial (i.e., the British stamps with check letters). The QoT stamps had check letters, but it became clear that these were not arranged in a logical sequence. The plating became something of a competition between E.L. Pemberton in England and J.-B. Moens in Belgium, and was published in the journals of the 1860s. It is interesting to note that in doing the work, Pemberton identified an "error of transfer", i.e., one of the substituted transfer pairs.
Bill Purves intended to publish a book on these stamps to follow his Half-length book published in 1953, and his brief preface to this proposed book has been included in the new volume. Purves eventually accumulated over 7,000 stamps (actual or as photographs) in an attempt to identify all the printing stones used for the lithographs. The present authors have almost doubled this number.
This work has confirmed that the two printing contracts of Campbell & Co. and Campbell & Fergusson that followed Thomas Ham's engraved printing, and totalling 3,500,000 stamps, were made using 13 printing stones, nine for the Campbell printings, and four for the Campbell & Fergusson printings. All the printings were made from stones made up of transfers taken from Ham's 50-on steel plate, and the total number of different positions which need to be identified to complete the plating is 1,900. This large task is only possible due to two factors - the check letters which immediately identify the position of any stamp in the transfers of 50, and the decision to increase the inland letter rate from 2d to 4d from 1 July 1855, but not to issue a 4d stamp until January 1857, meaning that the QoT stamp was used as pairs in very large numbers. The plating is not complete, because one stone (Campbell Stone 1) is rare and not all positions from this stone have been seen, and Campbell Stone 9, which comprises 300 units and not all positions have identifiable flaws.
The new work also addresses the complex problems of the numerous shades of these stamps, and provides a number of indicators for collectors to be able to divide their stamps between the Campbell & Co and Campbell & Fergusson contracts, which has been a problem for most collectors for many years.
