This is called "Flat Field" devices. They are seen only on proof coins. Why?
Because the proof coins are struck twice. So any Machine Doubling
on the first strike of the coin happens, the second strike will flatten it. This happens on regular dies and doubled dies.
Often on Variety Vista, you will see this affect, but it has nothing to do with the hub doubling of the doubled die. So always check the Description
box to see what is hub doubling. http://www.varietyvista.com/12%20Ke...4PDDO028.htm
Description: Medium quadruple spread on RTY of LIBERTY, and 4 of date, with light triple spread on WE TRUST.
They don't point out Flat Field doubling as it is a striking issue, not a die issue. Why does that make a difference?
Because the strikes cause this, not a doubled die issue on the dies. So it can happen on either types of dies, and can been different from strike to strike. So it is not a doubled die.
That is what you are seeing on your coin. Not as strong. The Flat Field doubling will be flat
(thus the name), but a doubled die will be raised on the coins devices enlarging the devices. The FFD is not a die issue, but a striking issue. CoopHome
: What is flat field doubling, and why it this not a doubled die?
FFD happens during the strike, and not a die issue, but machine movement issue during the strikes (proof coins are struck twice or more on some designs)