Don't Be Extreme With Magnification|
September 20, 2013
Please bear with me this time while I revisit the suggested powers of magnification to use while examining your coins. Just after my Aug. 20 column advised readers to use less than 10X magnification for grading coins, one reader wrote concerning some problems arising from the use of a digital microscope that magnified coins up to 200 times.
He felt that all his coins looked beat up and might be overgraded. That’s the main problem with over-magnification. Actually, most defects on a coin viewed from 20X to 200X are not significant. Many experienced numismatists are of the opinion that at high powers of magnification “you can’t see the forest for the trees.” That’s probably what the letter writer has observed with his digital microscope.
Digital microscopes are cool. I’ve seen them at major coin shows. While I don’t like the type and intensity of light they require and have not “cranked” one up to 200X, I shall make a point to do that the next time I see one demonstrated. It appears they may be an excellent teaching tool for authentication as several students can view the same coin on a large monitor.
Let me express the point I made in my Aug. 20 column again. You do not need high powers of magnification to grade coins. Walk the aisle of any coin show and you will rarely see anyone actually using a hand lens to examine coins or paper money. Authentication is a different story. For purposes of experimentation and study, I have viewed a few coins using an electron microscope at extremely high powers.
For example, you can find micrographs of the metal flow up the edge of a tiny “D” mintmark in the American Numismatic Association’s reprint of articles from The Numismatist. I have also viewed many coins at 80X long ago while I was honing my authentication skills. That was then. Now, I cannot remember the last time I ever looked at a coin using more than 40X because most authentications are done at 10X. So what good is a stereo microscope and high powers of magnification? Let’s take a look.
While at work, I take a coin from its flip and using my eyes alone under incandescent light (except on rare occasions), I can judge if a coin is genuine with unaltered surfaces and its final grade within a half point either way. Then the coin goes under my scope. Using both eyes, fluorescent light and 7X, I confirm my initial findings while looking for any defects that may alter my opinion. This is when I judge the actual amount of detail remaining on the coin due to wear, strike weakness, or worn dies.
The letter writer said that he downgraded his coins using high magnification. I believe this was due to inexperience and unfamiliarity with a microscope. A coin’s grade should never drop significantly (65 down to 63) due to the amount of magnification used to grade it unless a closer examination reveals something not immediately obvious to the naked eye.
I teach students that they need to be able to examine a coin and see every plus and minus characteristic so they can make an informed opinion on the merits of the piece and whether to buy it. Once you have made a complete appraisal of everything there is to see on a coin (No matter how high the power of magnification you use) it might be necessary to “step back” just a bit so as not to be too critical.
The majority of “vintage” coins are not found in grades above MS-64. Most old coins also have defects due to damage or mistreatment. That’s why a grader cannot be too critical.
Let me share a true story from long ago as I don’t want this to happen to my readers. One of my students one summer was a coin dealer. The next year his partner, another dealer, attended the grading course. During class he mentioned that since taking the course, “John Doe” had not bought a single coin all year. It brought a round of laughter to the class. I’m pretty sure he was exaggerating just a little. I certainly don’t teach grading so that students will not buy coins. I teach students to be as critical as myself so that they will know what they are buying and there will be no surprises to come later. Remember, coins over 50 years old are rarely perfect.
What a microscope does for grading is to let you see more about a coin quickly. Another benefit is that you will be able to better identify the things you see on coins using a hand lens much faster because you have seen them before using the scope. I’ve written before about how frustrating it is to see professionals debate whether a coin has a scratch or adjustment mark when the correct answer should normally require just a few seconds for folks trained on a microscope. With just a little study using a microscope, it will become easy for you to differentiate weak strike from wear, bagmarks from planchet marks, roller marks from scratches, and die polish from hairlines, etc.
If you ever get the chance to view your coins using a microscope, it will open a whole new world for you but don’t get too caught up in the high-power game. Additionally, don’t forget to take the coin out from under the microscope so you can judge it on the merits of its eye appeal. Want proof? Look at all the marks on the cheek of this Morgan dollar in Figure 1 at 40X. Figure 2 shows the same coin at 7X. Where are all the marks? Incidentally, this coin has been graded MS-64+ by one of the largest grading services.
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On September 24, 2013 Jim Morgan
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