Though all Indian stamps were being printed at the India Security Press at Nasik since 1926, but for 75 commemorative stamps issued in the period Dec.'59-Nov,'65, which had the printers' name indicated on each stamp, no other issues carried the name. A departure from this practice was made in the Fourth Definitive Series issued in the period 1965-75.All denominations in this Series, except the 3p,6p and 8p issues (which had been issued prior to the taking of the decision, and were short lived), had 'India Security Press, Nasik Road' printed on one of the sheet-margins.The inscription was followed by a code number consisting of a letter and numerals. The letters stood for particular denominations viz.,'X' for 2p.,'T' for 4p.,'A' for 5p.,'B for 10p.,.and so on upto 'N' for Rs .10, and the numerals were meant to record the number of sheets printed_a unit indicating 1,00,000(?)
This practice was continued for all subsequent series of stamps,though the introduction of new denominations forced the use of the same letter for different denomination, sometimes even in the same Definitive Series!
Apparently, computers were brought in at Nasik in early 1985 for the counting of printed sheets. While in the earlier issues the printers' name and alphabet-code appeared to be type-set, indicating that these were printed at the same stage as the stamps-design , in the later issues the numerals were in digital type, which meant that these were put in by computers at a later stage. In these printings, the location of the press was spelts as 'Nashik Road', instead of the earlier from 'Nasik Road'.