I'm still spending some time with my Proof Sets. Checked my 1968, and of course I checked the Dime first. Mine has the S mint mark. So sad! So, let's look at it another way. OK, if this is MD I won't be surprised, that's the way things go for me. If it's MD, it's the darndest that I have seen.
One thing that is very common to proof coins is that the mirror finish of the fields reflects the image back just like a mirror would. Chris
Visit this web site, and then come back with new images . http://varietyvista.com/07 Roosevelt Dimes/DDOs 1968-S.htm Then I can help ....
I don't have the capability of getting photos that clear. 1, my coin is still in the holder and at this time I don't think it wise to crack the set. 2, I don't think my phone can get a photo that clear.
This may be "flat field doubling" which can occur on proofs. We are familiar with Mechanical Doubling and that can happen on proofs as well, but modern proofs get struck twice. If the MDD happens on the second strike you just have MDD, but if it happens on the first strike, the second strike can smash that "shelf" spread it out, and flatten it down to the level of the field.