The 1840 Penny Black was the first official one of these
... A substantial number of these have survived, largely because ... printing plates 
were used (plate 1 is usually differentiated into plate 1a and... [DOC] [TLE] British Stamps - Line Engraved Issues of 1840-1853 [PAR] The line engraved British stamps, first issued in 1840 and 1841, were the first ...