Magnification 101 for Coin Cleaners
by Mark Farrell
Part 1: Overview
The information in this article is organized around the following topics:
Part 2: Motivation - why do I need magnification?
Eventually, coin cleaners get to the stage where they want to move past simple soaking and brushing. This could involve picking some stubborn dirt out of the crevices of a device on a coin or from around letters in the legends. This leads to a need for some degree of manual cleaning using various tools for picking, scraping, or.
Coins are small and cleaning them using picking, and other, tools requires that you see the coin in greater detail. By magnifying the coin, you are able to clean it more effectively while minimizing the risk of damage to the coin.
There are other values of magnification to coin collectors in general:
Part 3: Summary of Magnification Options
First, let’s get clear what magnification is and how people refer to it. From www.wikipendia.org: “Magnification is the process of enlarging something only in appearance, not in physical size.”
So, magnification makes something appear larger. Very simple. Magnification can be expressed as a number that is the ratio between the apparent size of an object and its true size. So, an optical magnification of 3, often called also “three power” or “3x”, means that the appearance of an object is tripled in size.
Magnification can also be indicated by the term “focal length”. So a magnifier can be sold as being three power or having a focal length 4 inches. In this instance, these terms mean the same thing.
So, how much magnification do you need? The first thought is to get as much as you can, right? Actually, no, because at some point greater power becomes a problem. Too much magnification can actually interfere with your work because by showing only a very, very small portion of the coin, you loose perspective on the overall process.
Too much magnification can also cause you to over clean a coin. By making such miniscule details very visible to you, you clean well past the point you need to because the coin is not likely to be viewed at that magnification again! People don’t appreciate your coins at 20x. They do it by holding it and seeing it at its actual size (even if they are middle aged and bring it closer to their eyes and squint at it).
If the detail you are attempting to clean is complete invisible at actual size, leave it alone – you don’t need to clean it further. Excess magnification can distort your perception regarding how dirty a coin really is.
So, how much power do you need? Here are some guidelines – your experience may vary:
There are many different ways to get the magnification power you need, and most of them are fairly reasonably priced. In subsequent messages, I will focus only on those that allow you to function hands free. You really need two hands to clean the coin – one to hold the coin and one to hold the tool. This means you can’t use magnifiers that don’t support themselves.
However, you may need some optical oomph when not cleaning, such as when attributing a coin. In this case, hand held magnifiers are very useful. They are many, many different types and sizes and powers. I have several that are have plastic or glass lenses. Prices vary widely, but a few dollars will get you a decent one.
Another handy tool when not cleaning is the type of jeweler’s loupe that folds into its body when not in use (see image). These come in a wide variety of powers. The better ones have glass lenses and metal bodies and can sell for around $10. Cheaper ones may be made all in plastic and can sell for as little as $2. These are extremely convenient because you can toss it into your pocket or purse and it won’t get damaged.
I have one of these jeweler’s loupes that actually has three lenses that you can combine to get 5X, 10X, or even 15X just by swinging in the different lenses. Very handy at coin shows!
Part 4: Overview of Free-Standing Magnifiers
In order to keep your hands free for working on a coin, the magnifier must support itself. The simplest solution is to attach legs to a lens so that it holds itself off the table. Indeed, these types of magnifiers are available.
They can be made in metal (more expensive and robust, perhaps $10) or plastic (cheaper, $5). They can be round or rectangular. They typically have a magnification of around 10X. This would seem to make them ideal for our purposes, but this is far from the truth.
Varieties of these types of magnifiers are designed to fold up when not in use. These are available in plastic or metal and range from $5 to $20.
Examples of these types of magnifiers are shown below.
Part 5: Overview of Magnifying Visors
A better, hand-free option is a magnifying visor. These can be attached to a head band that positions the lens in front of your eyes. The most useful variety is one that lets you swivel the lens out of the way when you don’t need it. Others, which are usually less powerful and are less expensive, hard-wire the lens to the head band so that to move it out of your way, you have to remove it from your head.
The first of these are frequently called “optivisors”, which is actually a brand name for a popular (and well regarded) type. The better ones have ground glass lenses and very stable attachments between the head band and the lens holder. Some of these even support optional accessories such as battery-powered light sources and added magnification loupes that rotate in and out as needed (I actually use one of these on one of my visors – it can be handy). Lenses are available in powers ranging from about 1.5X up to about 3.5X. Lenses are not cheap – better ones cost $25-30, which is in addition to the frame/head band. Even so, a total arrangement can easily reach $60. I actually have two of these. One has a 1.75X lens and the other has a 3.5X lens. I have two because I got tired of switching out lenses.
The second variety, which is the hard-wired type, is less expensive and is typically sold to crafters. My wife uses one when she does needlework (she also uses it sometimes when she’s reading, but only when she thinks I’m not looking). Magnification is typically a bit low for our purposes, in the range of 1.5X to 1.75X. Cost for these can range from $20 to $40.
The advantages of an optivisor is that it is very portable (I pack coins that I clean while away on business trips), has the minimum magnification recommended (at least if you get the highest power lens), and is somewhat affordable. Furthermore, it gives you enormous flexibility in how you want to work while the orientation of the lens to your eyes is largely fixed, you still have the ability to move about, shifting slightly as needed to get a better view, tilt the coin, etc. Finally, illumination with these visors is very simple. You can also use it for many other purposes, hobbies, crafts, etc.
Another somewhat newer option that I have not yet explored is a magnification lens that clips onto or slips directly onto your eyeglasses. You may see these for sale online. Let us know if you have any experience with these you would like to share.
One slightly negative note is that as the lenses increase in power, you have to move closer and closer to the coin in order to focus. Eventually, with the highest power lens available for these visors, you may have to be within 4 to 6 inches, which can limit illumination options and provides less area for working. And yes, you will look like a complete geek when you use one of these (especially if you equip it with the battery-powered light), but coin cleaning is neither for the meek nor the stylish.
These are readily available at many online stores and also at local craft or hobby stores.
Part 6: Overview of Swing-Arm Magnifiers
Swing-arm magnifiers, see sample photos below, are perhaps the best compromise between cost and usability. They will frequently incorporate lenses that are much larger than any of the other options, even ranging up to 6 inches in diameter. I’d suggest 4 inches as a minimum. In this measurement, bigger is better. Different magnifications are available, but I’d suggest looking for one that does 2.5X or 3X at a minimum up to about 5X at a maximum. If you go much above 5X, you are getting so close to the coin that you begin to loose working room and, depending upon your source of illumination, it can get really hot!
Most of these magnifiers overcome the inherent limitation that they have to “cover” the coin to be useful by integrating a light source. Least expensive models may simply use a 40-60W incandescent light. Better ones use a circline fluorescent bulb; these completely encircle the lens so that the light bathes the magnified object very evenly. Be warned – the more “interesting” the bulb gets (circled, highly specific wattage, etc.), the more difficult it gets in finding a replacement.
The length of the swing arm can also vary, as does the attachment of the magnifier to the table. Most are built to be clamped onto the edge of a table or desk. Others rise from a base that is typically very heavy because it has to keep the magnifier from tilting over, regardless of how far the arm is extended. The hoods of these magnifiers, which contains the lens and light source, also tend to rotate so that it becomes fairly easy to get the lens into exactly the position you want.
I, perhaps because I wear glasses, have a small problem with these big lenses – I have to hold the coin in my hand while I work on it. Otherwise, looking through the lens when it is at a slight angle, e.g., when it is positioned over a coin lying flat on a table, causes some excess glare as well it being difficult sometimes to focus on the coin. I cannot work in this position for long. Frankly, most people don’t have this problem.
Swing-arm magnifiers vary in price from the cheapest being about $20 (incandescent light, 4 inch lens, 2.5X to 3X, less sturdy arm and base attachment, etc.) to as much as $70 for a very sturdy one with the most powerful and largest lens. It is reasonable for most people to expect to spend between $30 to $40 on a decent magnifier.
These are widely available both online and at local hobby and craft stores, as well as at higher-end art stores. I strongly suggest trying out different ones to find the type that works for you best, even if you subsequently order it from an online resource. The quality of magnification and construction needs to be experienced if you are to make the most satisfying purchase.
Part 7: Overview of Stereo Microscopes
By far, the most powerful tool for a coin cleaner is a good stereo microscope. These have two eyepieces (see illustration below) so that you can focus on the object and really see the dimensionality of the surface. This is critical if you are using tools such as scalpels that can damage a coin easily if you are not careful. Furthermore, they can damage you if you are not careful – the hardest thing for me using a scalpel through the microscope was learning how to avoid sticking and slicing my own fingers!
Typically, these microscopes have two sources of illumination integrated into them – one that illuminates an object from underneath and one that illuminates the object from above. The first of these is fairly useless for coin cleaning. The internal light source can be augmented by purchasing a small, halogen or fluorescent light source that you then place as directly against the turret (where the final lenses are located) so that the light is projected almost vertically onto the work surface. I purchased such a light from a local office supply store for about $10.
Most of these microscopes have two magnification options. You move from one to the other simply by turning the turret. Typically, they are paired as follows:
The best combination is anything that includes 10X magnification. I frankly think that the best of all possible combinations would be 5X and 10X, or perhaps 10X and 15X, but I could not find one that supported that mix, so I went with the 10X and 30X version.
Initially, learning to use one of these was somewhat of a challenge. You cannot see your fingers so you have to literally feel your way. The tool you are using may look enormous because of the magnification. The coin’s surface will look completely different at 10X – it can be a challenge with certain types of dirt and patina to identify what is dirt vs the coin itself.
Even so, a stereo microscope is usually the way to go for detailed mechanical cleaning. It is not, however, for everyone. One of the best coin cleaners I know doesn’t like to use a microscope. But he is so experienced that he can sort of “feel” his way using a lower powered swing-arm magnifier. This works beautifully for him.
A decent, basic stereo microscope will cost $250 from an online distributor. I have heard that sometimes these are available on eBay at a significant cost savings, but I cannot vouch for that.
Part 8: Overview of the Ultimate in Magnification
So, what if you had all the money in the world to spend on a magnification tool? What could that look like? What would be the bottom line hit to your wallet?
Here are some features to look for if money is no object:
Many of these options can be mix-and-match with higher end microscope manufacturers, but again, you will get what you pay for. So expect to pay. If you wanted all of the options above, it would easily break $2000 with even a lower-end microscope manufacturer.
Part 9: Conclusions and Wrap Up
So, here we are. I hope you understand more about the options for magnification and that I’ve offered some options you may not have previously considered. Like many other things, you have to let two things determine where you go with a magnification tool:
I worked for six months using only a cheap swing-arm magnifier I bought as a discontinued item from a local office-supply store for under $20. It has long since been replaced. My primary magnification is provided by a stereo microscope that I bought online. I also use a bigger, higher powered swing-arm magnifier that has an enormously heavy base (and two Optivisors with different lenses and a handful of hand-held magnifiers – I am embarrassing myself). The more you do, the more you need.
Be realistic with yourself. If you only clean an occasional coin, you need less optical oomph. I am one of the badly addicted cleaners in that I do it every day, sometimes several hours a day. It is a big passion for me, so I have more equipment.
Because I am more interested in educating people on the joys and methods of cleaning coins, I am pondering purchasing a scope with integrated video. Wouldn’t that be a great way to help bring people up on a more powerful cleaning option (or so I tell my wife, who isn’t buying it yet, and balks quite fairly on the price tag which is over $1000).
Remember this: when it comes to spending money on tools, be realistic with yourself. If you really don’t need it, then start more simply. Every dollar you spend on a tool is a dollar you can’t spend on coins or on coin reference books.
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