If anyone interested, here the affixed stamp Br. India 1856 ½A SG 38 is printed from die subtype IB.
The master die for the entire 1856-64 East India series was prepared without the denomination.
Punches were taken from the master die and the denominations were engraved singly on punched dies which were used to make the plates.
The printer of East India series Thomas de la Rue and Company asked the Board of Inland Revenue on October 13,1857 to grant permission to prepare dies for the entire East India series from a reengraved master die as by then due to the hight quantity of printing, the plates, mostly of ½A and 1A values, were worn out.
In this phase, the head was taken from the original master die but all the letterings were newly engraved on the punches, separately, which resulted East India ½A die I with letterings of East India ½A die II, which has been classified as die IB which thus is the intermediate die between die IA and die II, having hybrid characters of both these 2 dies.
Die IB has head of die IA but letterings of die II. Both the die IA and die IB show the characteristic feature of closed mouth of Vic. head which is the foremost identification criterion of EI ½A die I.
The two subtypes differ only in the pattern of letterings.
Both die IA and die IB extended to the 1865 elephant's head watermark printing.
The relative scarcity of these 2 dies for 1856 unwatermarked series is 60-65% die IA and rest is die IB and for 1865 watermarked series, only 2-5% is die IA and 95-98% is die IB.
As usual, hopelessly Gibbons does not catalog die IA and IB subtypes of East India ½A stamps.
