The Liberty Series regular postage stamps of the USA were issued during a time of technological printing innovations at the Bureau of Engraving & Printing in the 1950s. The major change involved new printing presses which could produce intaglio line-engraved stamps in single colors at faster speeds and improved costs compared to older presses. The new presses did not require pre-moistening of the paper as the old presses did; hence the generic name of "dry-printing" for the process, compared to "wet printing" prior. The new dry-print process did require new quick-drying ink formulations, stronger paper, and higher print-roller pressures. These differences culminated in stamp output that appeared slightly brighter and glossier than before, on paper which appeared whiter and smoother.
Some of the Liberty series ordinary stamps were printed on both older presses (wet-printed) and later on new ones (dry-printed), without advance notice to collectors about the dry-print change-over. Specialists enjoy collecting both types of these varieties. For postal history buffs, one challenge is to find "earliest documented" usages of dry-print stamps when both print methods were used for a design. The chart below attempts to post up-to-date data on what postmark dates are now known for the dry-print varieties.
(Resources available about dry printing are at bottom.) [Go there now.]
| *--approximate release date as noted in Scott Specialized Catalogue of U.S. Stamps & Covers. |
| #--lowest 432-subject plate# as noted in Durland Standard Plate Number Catalog, but some |
| 384-subject (large-hole) #s are higher. |
1. The Liberty Series study group has a page posted from a July 1970 article of The United States Specialist illustrating the cross-hatching marks that appear in the electric-eye dashes of dry printings. The link is: Dry-Print EE Engraving Style
2. "The Liberty Series: Collecting Wet and Dry Printings on Cover" by Anthony S. Wawrukiewicz; The United States Specialist, April 2000 (Vol 71 # 4), pp.179-184.
3. "Lowly 3c Stamp Object of Intense Hunt" by Ronald Blanks; U.S. Stamp News, July 2006, pp.13-15.
4. "A Little Known United States Stamp Specialty 'Wet and Dry Printing'" by Walter G. Taylor; The United States Specialist, July 1970 (Vol 41 # 7), pp.265-275.
(Last updated 24 May 10) (email contact: rblanks_stamps@yahoo.com)
If you are interested in inexpensive used singles (off-paper) of the Liberty dry-print varieties, I offer duplicates for trade at my website, ==> Used Liberty Series stamps.
