– How does the post office differentiate stamps from stickers, and how has this changed throughout history?

Question

Stamps have been used since the mid 1800s to send letters and there must be tens (if not hundreds) of thousands of stamp designs and denominations. How are they tracked?

In: 6

Answer 1

If I recall, stamps have uv ink printed on the backer paper showing the denomination. That ink is visible to the sorting machines which detect “sufficient postage” or “invalid/insufficient postage” and kick the letter out of the sorting machine for manual verification. Modern stamps can also have qr codes on them which are read for the denomination.

Answer 2

If I recall, stamps have uv ink printed on the backer paper showing the denomination. That ink is visible to the sorting machines which detect “sufficient postage” or “invalid/insufficient postage” and kick the letter out of the sorting machine for manual verification. Modern stamps can also have qr codes on them which are read for the denomination.