Proof and Mint State Coins - A Photographic Study on Rim to Edge Junction and Distinction
FlyingAl
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In my turkey induced hallucinations (Happy Thanksgiving!), I figured I'd go ahead and show one of the major differences between Proof and MS coins in the more modern era. The junction between rim and edge is often the most minor of tells, but when it comes down to it it can be the most reliable. The study below is for mid 1960s coins, but from what I see in my own personal collection it rings true for at a minimum the 1936-42 era of coins, and looks to be correct for the Barber and Morgan era.
Both toggle and medal presses imparted a different force profile onto coins, which caused medal press coins to show a much sharper and well defined junction. The use of a different collar on medal press coins also helped create this difference.
Below I will place several comparisons between Proof and Mint State examples. While direct dates do not match, this study still shows the difference between the two types of coins. It is of note that all comparisons were taken in identical photographic conditions.
MS and Proof Half Dollar (Kennedy):
The Proof example will show little to no rounding in the rim to edge junction, while the MS coin does. This is especially visible in the reverse images near the edge reeding. An altered reverse image shows the notable areas in red.
PROOF OBV:
MS OBV:
PROOF REV:
MS REV:
MS and Proof Roosevelt dime:
Similar differences can be seen in these coins as well, but they show slightly differently. The MS coins show more of a "divot" in the images whereas the Proofs still show strong junctions.
PROOF OBV:
MS OBV:
PROOF REV:
MS REV:
MS vs. Proof Lincoln Cent:
This is the most obvious and most notable of all the comparisons, due to the fact that the rim is not distorted by reeding. The Proofs show nearly no edge to rim distortion, while the MS coins show obvious shearing (shown in the highlights that are lacking on the Proof images). It seems I neglected to take reverse images, but as you can see from the above the characteristics are the same on both sides of the coins. If you'd like to see reverse images, I can do that.
PROOF OBV:
MS OBV:
As we can see from the above, the differences are quite clear.
Can this help with authentication from normal images? It can. See the below images, starting with a 1955-S dime obverse. The area circled shows an area of shadow in the images - that area corresponds to the area of weakness shown in the images above. There are other areas like it on both the reverse of the dime and obverse and reverse of the cent.
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Now compare to images of Proofs - those areas of shadow aren't present (except that those of you with good eyes will see there is actually some shadow at the top of the Proof cent, which does correspond to some minor edge shearing on the coin in that area. This is a testament to the accuracy of this method, since the shearing is rather minor and seems to be due to the thinness of the edge at that point). 
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How does this work with images? The camera, when taking a facedown shot, will catch areas where the depth is different and will give it a different area of color, either shadow or highlight (dark or bright). For MS coins, the camera shows the rolling of the junction as shadow. For Proofs, where there is no change in depth due to a lack of rolling, the camera will not show any shadow or highlight - there's nothing to show.
Therefore, a simple check for shadow on images can show whether a coin was struck in a medal press, or a toggle press.
To conclude, I'll put in some fun shots I did tonight. If you'd need any circles on the above images to understand better, I can provide those. 
Coin Photographer.
Comments
You’re absolutely amazing!
I also read your phenomenal research article on a different subject in the November 2024 issue of The Numismatist, ANA’s scholarly publication, which they chose to use for their cover story!
And you’re still a teenager?
WOW!
Steve
FlyingAl Fan #1
My collecting “Pride & Joy” is my PCGS Registry Dansco 7070 Set:
https://www.pcgs.com/setregistry/type-sets/design-type-sets/complete-dansco-7070-modified-type-set-1796-date/publishedset/213996
Great pictures and description. I frequently have problems with high end MS and the SMS from the 65-67 years. If youhave a couple hours before back to school, a comparison of them would be nice.
What does this picture show?
Thanks for a nice thread.
What do I think the most important aspect of the thread to be?? You have highlighted the importance of learning how to grade. With a little diligence ANYONE can learn these things if they want to and put forth some effort. I always try to stress the importance of grading and other basics of the Hobby but way too many cheat themselves out of laziness, it's too easy to pay someone else/some service to do that.
I applaud @FlyingAl for putting forth the effort to learn.
Thanks for the great photos and explanations FlyingAl!
FlyingAl Fan too.
If nobody else will ask I will. Provide the circled areas please. james And tanks in advance.
While I don't have a SMS set handy for images, you can analyze them using the techniques I've described above.
The SMS coins show some Proof characteristics (not much rounding), but also show some MS characteristics (more rounding than a Proof). This is consistent with a coin struck on a toggle press at high pressure. Incidentally, that is how we know those coins were struck. Overall, the characteristics trend Proof.
The 1964 coin in your post is a mechanical error Proof.
I will try and provide circled images later today.
Coin Photographer.
I'm glad to see you got out of it what I wanted people to get out of it!
This thread highlights how the most minor of details can be the make or break for some coins. For example, this 1881-O graded as a Proof does in fact show Proof characteristics. Documents seem to corroborate its status. Other coins are not so lucky.
Coin Photographer.
Alex, what’s the documentation you referred to?
Thank your efforts and for sharing them.
Mark Feld* of Heritage Auctions*Unless otherwise noted, my posts here represent my personal opinions.
Mark, PM to be sent.
Coin Photographer.
@seatedlib3991:
Proof 1c shows a strong rim to edge junction (no shearing is visible).
MS 1c shows a very weak rim to edge junction (strong shearing is visible).
Does that help with the above? The red areas marked in the images above will correspond to areas of shadow in the head on shots.
Coin Photographer.
Thanks for this excellent post and your excellent Pics!
LOl, I just took what seems like 50 pictures of a newly arrived 2024 D cent. Those of us who photograph know the difficulty of shooting proofs. But I got to say those Shield Lincoln's are impossible. In Fact, I even looked at the Trueviews to see what I was missing...Well let's just say mine are dark, but they look a lot better than the Trueviews! I will try again another day.
WS