The famous penny black, the world's first postage stamp, was introduced in England in 1840. The idea of postage stamps was a great success and was taken up worldwide. Yet the penny Black was in use for only one year before it was replaced by the Penny Red. Why?

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The postmark used at that time was always black. It was therefore difficult to tell whether a stamp had been frankled or not. This led to people reusing used stamps. On a Penny red the black postmark was clearly visible.
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