Basin
Basin. The concaveness or sloping surface of a model or numismatic item. A die in this shape is said to have a camber. The basin is formed by the rim and the dished area of relief. Coin models particularly are so shaped because of the requirement of a rim higher than any point on the relief and the fact coins are struck from a single blow. A background plate in this dished shape is also called a basin. The St-Gaudens 1907 $20 Gold ultrahigh relief is the most dramatic U.S. coin with a basin.
Also the term basin is used by mints for somewhat smaller models while “background plates” is used for medallic art, often in a larger size. Should the design be flat without any concaveness certain modern diecutting pantographs can create a basin shape and cut a die with a camber. See BACKGROUND PLATE, die camber.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