Since MD is caused by a slight bounce or a shift of the die as it strikes the planchet wouldn't we expect to see the same doubling and of the same "strength" on all devices equally? What got me thinking about this is this PR 1968 Lincoln Cent I'm looking at. IGWT has some very heavy MD. Moving south, the eye is doubled, then the nose. Then even less on the chin and by the time we get to the date and MM there is almost none. oh wait...I guess it's possible for a planchet to not be sitting ABSOLUTELY level as it's struck? Did I just write all of this and answer my own question or is there something else?
See the new website created by Mike Diamond, Sullivan & Weinberg. Just google it. There are various form of shift doubling. JPL
"You must also remember that proof coins are struck twice." I believe proof coins are struck just once on a hydraulic press. I'll check on this with Roger Burdette to make sure but I think the "struck twice" thing is a misconception.
From the Mint: "U.S. Mint proof coins feature sharp relief and a mirror-like background. Their frosted, sculpted foregrounds give them a special cameo effect. Proof blanks are specially treated, polished, and cleaned to ensure high quality strikes. The blanks are then fed into presses fitted with specially polished dies and struck at least twice to ensure sharp relief. The coins are then packaged in a protective lens to showcase and maintain their exceptional finish."
