DDO=Doubled Die Obverse.
DD= Doubled Dies
I'm guessing that is not what you were asking. But you probably meant DDD
On a doubled die, during the mint process of creating a die, a hub is used to create the die.
The hub is like a coin. It's a positive design, just like a coin. But transferring this positive to the new die blank, makes the die, a negative. (Mirrored) the fields are the outside of the die, the highest points on a coin are the deepest part of the dies. So if the hub process is not aligned correctly, a doubled die can be created.
All coins struck with this die, will be a doubled die through its life.
, this is a die wear issue. The devices were all normal until late in its life, it is altering the devices, not on the devices, but on the fields. On the single squeeze dies, they are different from the multi-hub examples of the past. On the single squeeze dies, the profile is lower, than in the past. So it alters the fields, not the actual devices. This appears on all devices towards the closest rim direction. What is posted here are examples of this happening, but also some of the images I posted are advanced DDD
. Advanced how? In the sense that now, the devices are now being affected.
You are beginning to see distortion on the outer edge of the devices and inner edges of the devices. Most of the time these dies don't reach this stage, but if continued to be used, will show the later stages of die wear.
But this die wear/DDD is not a collectible. Just like wrinkles on a senior, there are no premium for these. These are spenders. Unless you want to save them to show to a new collector. So the differences? One coin, the DDO/DDRs are Variety coins. They are premium coins. The DDD
are no premium as they are just worn out normal dies. Spendable coins. But knowing the differences is the gold of collecting. Find one, you save it. The other on, you move on to the next coin. I hope this is the answer you were looking for. Another difference on the DDD
, is it is a die event. A doubled die is a die variety. The variety coin strikes doubled dies from coin one to retirement. On DDD
, the die breakdown happens only at the end of life, when 54% of the coins will be the last ones struck. (Not a good thing) Then the die will be retired.