In the early days of automation the POD sought means of indentifying the stamp on an envelope to permit "facing" the envelope so that the cancel would fall on the area of the envelope which contained the stamp. It was already a requirement that stamps be placed in the upper right corner of the envelope by the machine cancelling process. The facer-canceller was the machine which was being developed. In practice the idea was to scan the faces of the cover and determine where the stamp was and then to orient the cover so that the subsequent canceller would strike the stamp. The result was the beginning of the development of a family of fantastic high speed machines for accomplishing this task. The key was providing stamps which could be identified by the machine. This was accomplished by providing stamps which flouresced under ultraviolet light providing a 'hot spot' which could be sensed by the detectors. Next, the envelope was turned mechanically to the right postition.
Here we will let the Williams brothers take over:"In North America, the first sale of phosphor-lined stamps, termed "luminescent" or "tagged," was made in Winnipeg on Jan. 13, 1962, with Canada 1962-64 1c., 2c., 3c., and 5c. In the United States, the first experimental "luminescent tagging," an overall coating of inorganic phorphors, occurred on stamps issued Aug. 1, 1963, at Dayton Ohio, U.S. 1962-63 Air 8c.; on Nov. 2, 1963, at Washington, D.C., the 1963 Christmas 5c. and the 1958-1964 Regular 4c., similarly tagged were put on sale. In Australia, tagged stamps with "helecon," a commercial name for a certain type of zinc sulfide, either incorporated in the printing ink or included in the surfacting coating of the paper, have been issued since 1963; the first such stamp to be issued there was Australia 1959-64 Regular 11d. Other Countries, including West Germany [for example, 1962 (May 10) Second Millenary of Mainz, 20p.] and Switzerland [for example, 1964 (Jun. 1) Pro Patria 5c. + 5c, to 30c. + 10c. have made similar issues. The German tagged stamps, called "lumogen," are identifiable by a yellowish overprint to the paper. Swiss tagged stamps on granite paper are identifiable by violet fibers, clearly visible from the back of the stamp under magnification."
Excerpt from Fundamentals of Philately, L. N. and M. Williams, Revised Edition, 1990, American Philatelic Society
Posted March 24, 2001
Index of 508 Notes from the Past
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