Lot 50074 – British East Africa – 1894 5a & 7 1/2a Surcharges, group of 16 items

British East Africa – 1894 5a & 7 1/2a Surcharges, group of 16 items including two highly valuable « 5 ANNAS. » & « 7 1/2 ANNAS. »engraved copper plates (very rarely encountered in the Sperati archives), each overprint in die proof on pelure paper, seven essays on wove paper including three with two impressions, as well as a rare 5a cliché on celluloid proving that Sperati also tried to reproduce this overprint in photolithography; the only copper plates recorded proving the experiment of the typographic option by Sperati (unknown to the B.P.A.), enhanced by a unique complementary group of items.