In 1934 the BEP began experiments with dry printing on flat plate presses. It was determined that the equipment currently in use was not capable of applying the pressures required to produce good quality impressions.
In 1939 the BEP ordered a heavier flat plate press and again began the dry paper experiments but discontinued the project due to the looming war. No dry print examples were ever release from either the 1934 or 1939 experiments.
In 1953 the dry paper printong project was revived. The BEP ordered a new rotary presss that they believed could handle the dry paper. In 1954 the first dry paper issue was printed on the flat plate, the Scott 1041 issued April 9, 1954. The first rotary press dry paper was tthe Scott 1063 issued July 28, 1954.
I believe the BEP only issue 5 dry paper flat plate issues (1041 on 4-9-54, 832c on 8-31-54, and the special handling QE1, Qe2 and QE3 in 1955).
The wet process used paper with a moisture content of 20-35% while the dry process used a moisture content of 5-15%.
Below is a pic of the first dry process rotary press.
