The events leading to the separation of India and Pakistan have been extensively dealt with in various publications over the years. Understanding the urgency in creating Pakistan's new stamps is essential to understanding the complex philatelic results.
The main security printer on the sub-continent, indeed the only one capable of producing the overprints urgently needed in sufficient quantities, was the Indian Security Press at Nasik. The Pakistan authorities received co-operation to the extent that they were able to have stamps overprinted there and these were brought into use on 1st October 1947, following Independence on 15th August. Supplies however, were rather unreliable, and it became necessary to authorise further overprints. These took place at various places around the new country, with a multitude of hand stamps, typewritten overprints and hand written overprints, prepared locally by people who wished to use stamps which were Pakistani in character, rather than Indian. No matter that some of the stamps found and used for overprinting and hand stamping were obsolete – anything that could be used was put to use.
As is usually the case when political upheaval necessitates provisional issues, study and recording of all the different types started almost immediately and continues to this day. Col. D. R. Martin's book on the overprints was published by Robson Lowe Ltd in 1959, and was later reprinted and updated in Pakistan (1972). Much further research was undertaken, both inside and outside Pakistan, culminating in the publication of 'PAKISTAN; OVERPRINTS ON INDIAN STAMPS AND POSTAL STATIONERY 1947-9', by Ron Doubleday and Usman Ali Isani, in 1993. This massive work is lavishly illustrated and authoritative.
The Nasik overprints were exceptionally well carried out. When it became necessary to supplement them, photographic copies were made in Lahore and elsewhere, and distributed to the other cities such as Peshawar and Karachi. Naturally, such copies lacked the precision of the originals, and this is where specialisation begins.
One of the most important things for the collector to do is to understand the necessity of accurate measurement; to quote Doubleday and Isani – "Always measure length in a straight line from the outside of the foot of letter 'P' (excluding any serif) to the outside of the right foot of the letter 'N' (again excluding any possible serif)". The full stop, which may not always be apparent, or any other possible traces of a hand stamp holder should be excluded. Height is taken from the letter 'I', unless obviously unrepresentative. In such cases the height of the letter 'K' should be taken." Accurate measurement is a vital first step in narrowing down the myriad of possibilities with the hand stamps. Even before the Nasik overprints became available (1st October 1947), and hand stamps and the local overprints went on sale (January 1948), there were some unauthorised local hand stamps, seemingly done by people who disagreed with the decision to continue using Indian stamps until the Nasik prints became available. Few of these early hand stamps have been recorded, most having apparently been used on telegrams. The imitations of the Nasik overprints are reasonably easy to separate, which is just as well. Although there were a number of errors, many of the more important ones emanated from Karachi, and the quality was reasonably high. The major errors on the 1r, which merit footnote status in Gibbons, happened there. Finding an example of the few King George V high values used for hand stamping or overprinting at one of the major centres is an unusual event – as is locating any!