Wet Or Dry Printing??.

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Paper was dampened prior to being run through the printing press up until the time of highly mechanized printing. There was good reason to do this. Dampening the paper softened it a bit and made the ink adhere better. But the added moisture made the stamp image not quite as crisp as it could have been.

Additionally, a bigger problem was that as the stamps dried they would shrink. Sometimes the shrinking was negligible, other times it was significant.

When mechanized printing came on to the scene, the dampened paper caused problems. It was softer, and large rolls of paper used in mechanized printing would tear if wet. Wet paper took longer to dry, made less crisp images and shrank. Printing directly on dry paper solved many problems associated with wet printing. The image detail was improved, there was no shrinking and the machinery used for printing was not compromised.

So that tells the how and why of wet versus dry printing, but stamp collectors also need to know the "what" part of the story: what's the difference between the two from a collecting standpoint?

You can both see and feel the difference between wet and dry printing. In wet printing, the ink on the stamp sinks into the moistened paper and even spreads slightly.

You can see that under magnification better than you can see it with the naked eye.

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It's just that the dry printed stamps were printed on pre-gummed paper where as the wet printed stamps were post-gummed after being printed and dried.

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The adage "You will know it when you see it" comes into play here. Simply put: the differences in detail will jump out at you.

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Pre-gummed paper was used for dry printing flat plate stamps and the sheet fed three color Giori press. The same plates were able to be used for later wet and dry printings of the Special Handling stamps as well as some Canal Zone issues and others. Rotary press dry printings were on different plates because the Huck-Cottrell presses used for dry printings differed substantially from the earlier Stickney presses.