I first noticed this on an extremely bright white coin that I purchased recently, then I noticed that they all have this to some degree or another; a "circle" that goes through the devices as well. I thought it might be a raised or depressed area, but when I drew a toothpick across it I could not detect any elevation difference. I am thinking it is related to metal flow somehow, but I don't quite see what is going on. Can anyone shed some light on this? Thanks LS
This is primarily seen on late die stage coins. It is less common on Walkers because they are thick coins, but this is an example of "ghosting" or "progressive indirect die transfer." Essentially, you are seeing the faint outline of the eagle on the reverse. The way the metal flows on each side of the die is not independent - the metal will flow to fill the high points on both sides of the coin. Over the life of the die, that metal flow will change the surface of the die. This effect is extremely noticeable on thinner coins (such as Lincolns). But all coins, after a long enough die life, will show it.
Well ... ah ... looks like you're right. I was a little skeptical at first because it doesn't really line up exactly with the eagle on the reverse, but I guess the operative word is "ghost" or shadow. I checked a bunch wheat pennies and sure enough every one I checked had a diffuse outline of Lincoln's back and head to some extent or another. For the benefit of others here's link that shows it on some other coins. http://www.error-ref.com/progressive-indirect-design-transfer/ . Btw, I bought your book recently and I am finding it a splendid and necessary companion to the Official ANA Grading Standards for United States Coins. Regards, LS
