quote:
Originally posted by bitters
As a point of clarification, several "prooflike" Morgans were posted in this thread. The prooflike/deep prooflike designation as used by the grading companies does NOT refer to the frostiness of the devices. In fact, they're not necessarily frostier than any other Morgan. The designation refers solely to the mirror qualities of the fields of the coin. The degree of mirroring is determined by the distance in inches that you can get a clear reflection off the fields of the coin. I'm not sure what actual values they use. Maybe 4" for prooflike and 12" for deep prooflike? Don't quote me on that. They probably just eyeball it, anyway, when they're grading the coins.
Now as for what causes the frost on cameo coins. In the older days, one of the steps of proof die preparation was soaking the dies in acid. This would create a frost over the entire surface of the die. The fields were then polished, leaving the frost in the recesses of the die (the raised portions of the coins). After a number of strikes, this frost would wear off the die, and you'd get brilliant proofs instead of cameo proofs. I believe in the 1970's, they started sandblasting the dies, followed by a polishing of the fields, to achieve this effect. Also, the mint became more concerned with specifically achieving this cameo effect, and replaced dies more frequently.
To expand on this excellent explanation, it should be noted that, at some point, workers at the mint began polishing the devices of the dies as well as the fields. This process removed the cameo effect. This is especially true of modern Proofs, produced since 1950. Proof mintages climbed dramatically due to production for collectors - before 1950, 20,000 was a very high number of proofs for any given issue, while since, mintages in excess of 3 million are the rule rather than the exception. For that reason, many more Mint employees were involved in the die production. Some of these employees polished the devices, some did not. That's why modern Proofs of that era can be found with and without cameo; given the low per-die mintages, a die which would strike cameos was probably capable of striking cameos throughout its' useful life.
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Posted 12/11/2006 12:45 am
