Just curious about this. I've noticed from many coins, most notably the ones that I have, Lincoln cents and
Jefferson nickels... The strike in the proof coins from the 50's and 60's is much different from that of the coins that came later. I don't know about other coins other than those... But I would assume probably a similar scenario?
I know Philadelphia produced many of the earlier proofs before San Francisco became mostly proof only, with exceptions obviously.
For example, it seems many earlier proofs have a more mirror-like strike, as opposed to a cameo or frosted effect. I personally like the more mirror finished ones.
I'm sure somebody will fill me in on this. Any thoughts?
Just for comparison take of what I'm talking about...

