In an earlier post there was discussion, if there are invisible cancellation to prevent postage reusing. I have thought it’s an urban legend, because I’ve heard it before, and didn’t find any proof it to be true.
(Then I tested and wrote: Edit. now I tested this. The neon orange barcodes are better visible with UV light, but nothing more, no extra invisible marks in postage stamps received from Finland, The Netherlands, Canada, USA, UK or Spain (but how many clear postage stamps ).)
But now, accidentally I hit the pen to a postmarked card, and it revealed some numbers.
I believe these are to prevent preparing fake postage? But I was really happy, and interested, to be at least partly wrong because now I think I must look all postage again.
Here I try to add some samples (the Sherlock stamps seems to have some text):
Thank you for testing! I’ve also heard that somewhere. Additionally, I heard that they have UV markings so that the machines can recognize where the stamp is located on the card.
I have noticed some hidden numbers on the received Chinese stamps ( with fruit, if I am not mistaken) recently. I guess they may be better seen with UV light.
BTW, there are hidden details on the Russian “Cats” series which can be revealed with the UV. The stamps on the right side.
I tested Finnish unused, the have the “€” mark better visible in UV light, but nothing more, and not after travelling either (both postmarked and non postmarked have nothing extra).
@Tetsuko The Canadian stamps are so gorgeous! I like it’s paw prints
@Kogotok7 yes, the fruit had the numbers too. These are lightly seen when I tilt the card, but better seen with UV light. (It’s hard to take photo of these since I only have a torch and pen).
The old style looking stamps from Russia, and stamps from Turkey seem to be prepared to paper with UV reactive fibers, like Finnish paper currency and passport pages.
@S_Tuulia Notsure about the other countries, but for the Royal Mail UK issued stamp, the UV coded message is intentional and part of the stamp design. It is suppose to be a hidden message.
).)
because now I think I must look all postage again.
