Impression. (1) The degree of pressure causing a greater or lesser amount of relief on a struck piece; the impression is gradually increased during set-up until the amount is perfect and the pieces are fully struck up. While impression may be considered how deeply the design is impressed into the metal blank, in reality it is how completely each die cavity has been filled. In effect, that every high point is present and fully formed. Thus pressmen examine sample strikes under magnification for this perfect state of the high points and that no die draw (a flow of surface metal into, then out of, die cavities) has occurred.
excerpted with permission from
An Encyclopedia of Coin and Medal Technology
For Artists, Makers, Collectors and Curators
COMPILED AND WRITTEN BY D. WAYNE JOHNSON
Roger W. Burdette, Editor