How do you see hairline scratches in dim light, like at a coin show?

I just received a coin (internet purchase) that has very noticeable hairline scratches when looking through a 10x loupe. But I can only see them reflecting the light when I bring the coin into direct sunlight. I cannot see them when looking at the coin indoors due to the low light level.

So, say you are at a coin show with dim lights...how do you detect hairlines? Is there a good loupe with some sort of built-in light for this purpose? Other ideas?

 

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One thing you might try is buying one of the portable LED book reading lights. They can be pretty bright and may help with detecting hairlines.

 

I'll tell you what helped me the most. After many years I bought one with really nice glass. I catch things I missed in the past.

 

Based on your reply, Doug, I found that I was just too far away from the light source when looking here at home. Holding the coin real close to even a low-wattage bulb showed the hairlines.

But to see them without magnification? You must have eyes like the Six Million Dollar Man. LOL

Thanks for all the replies.

 

I use a halogen desk lamp at home to examine coins, and it shows hairlines quite readily.

Chris

 

could you also tell the color of the apple that adm and eve were eating at 50 paces. We know that everyone measures their age in year but you do it in centuries

no wonder you are getting most grades wrong with these modern coins blame it on the poor eyesight

BTW its nice to see you again after many weeks

 

And if you are at a table where the light is away from you do not forget to nicely ask the dealer if you can move around to the light.

Hey spock where were you for this thread how old is he.....

 

well i happen to be travelling in space right now so i miss a few GD isms every now and then

 

As Doug mentioned, turning the coin under incandescent light is the best way to detect hairlines. I might add that if you tilt the coin at a steep angle, not quite vertical, and rotate it at the same time, you will have a better opportunity to see the hairlines since the hairlines will be more reflective when viewed this way. Hairlines on proofs that have been wiped or cleaned are much more easily detected due to the reflective surfaces.

Btw, in my opinion, just because a coin has hairlines does not necessarily mean it is less than mint state, especially in proofs. Many TPG graded coins in PF60-63 do have hairlines, and I personally think that mint state coins with hairlines can also warrant MS60-63 grades as well.

Last thing to keep in mind, some coins have die polishing lines that can look very much like hairlines, but these lines will be raised on the surface and not reflective, and will cast a very tiny shadow on the coin when tilted and rotated under light. Die polishing lines usually do not (or should not) alter the grade of a coin, while, of course, hairlines will.

 

Forgive me for nitpicking here, but I'm a bit of a lighting geek, and I can't help myself.

I'm guessing that most good numismatic references date from a time when incandescent bulbs were the only ones commonly available in small sizes -- a "fluorescent bulb" was a four-foot tube, and anything else (arc lamp, laser, etc.) was a specialty item.

A broad-area light source like a non-compact fluorescent hides some features, like the hairlines the original post mentioned. To reveal those, you want a small-area source or a point source. An incandescent bulb a few feet distant works reasonably well. (Direct sunlight could work even better, except that it's too bright, and not always available.)

I imagine that there would be no practical difference between an incandescent bulb and a CFL of comparable size and brightness. A high-intensity, small-area LED would probably highlight hairlines even more than a conventional bulb; this might be a good thing or a bad thing for grading.

I'm not sure color-spectrum issues come into play for grading, because you're looking at topographical features, at a scale where all colors of light behave the same way. (Of course, this neglects toning, where color rendition matters very much.)

If there really is an advantage to incandescent light other than the dimensions and brightness of the emitter, I'd be interested to hear more details. Do any of your references say anything about clear vs. frosted bulbs (which would affect the effective size/area of the source)?

 

It's pretty hard for me to prove things like this to myself, because I've still got so very far to go in developing my "eye" for flaws and damage.

I think most visible flaws on a coin reflect visible light of all wavelengths just about the same way -- again, excepting toning or other colored deposits. But eyes certainly perceive different wavelengths differently. In particular, blue light is harder for eyes to focus. Incandescent bulbs produce relatively low levels of blue light, while "cool" fluorescents or LEDs produce higher levels. ("Everyone" apparently agrees that this is actually better for car headlights; I have no idea why.)

Halogen lights can also put out a higher proportion of blue light, even though they are fundamentally incandescent.

I'd take pictures under various light sources, but "which light shows flaws better in a photo" is an entirely different question from "which light shows flaws better to the eye".

I was ready to guess that you see more under incandescent light simply because incandescent lights have long been brighter than fluorescent or LED alternatives. That can't explain their superiority to halogen bulbs, though. I would've guessed you would find halogen superior. So, my mental model is still wrong.

Ah, well, off to do more research. While I don't have a well-trained eye, I do have a number of different kinds of light sources, and I certainly have plenty of flawed coins...

 

Halogen

I've been looking for the answer to this question also. What I've come up with is a definition from PCGS: "halogen light A powerful light source that enables a viewer to examine coins closely. This type of light reveals even the tiniest imperfections." and a paragraph from Traver's "Coin Collectors Survival Handbook". His handbook states that halogen is a must to see hairlines on a proof coin. This wasn't an answer I wanted to read as a small (50 watt minimum is suggested) halogen desk lamp isn't all that cheap. Hope this answer isn't too late to help.

 

JeffB has a very good handle on lighting, and I agree with his posts in this thread 100%.

Point sources are best at detecting hairlines.

Incandescent and halogen are two examples of point sources -- and if the halogen is "too bright" simply move the light farther away (or buy one that is less bright). The ANA got that one wrong, IMO.

 

Leadfoot, this is almost funny. Following is an ad to sell a coin: "This one has delicate coppery-orange toning on both sides, and no signs of handling or hairlines, even under the severe scrutiny of a 10X glass and halogen lamp." It goes to show how many believe that halogen is prime method to prove perfection. Then, I read a piece from a retired NGC grader, he stated either incadescent or halogen, although he felt like halogen was "like looking into the sun. He also was against using low wattage incandescent as they created a yellow cast and partially hid the hairlines. It seems younger graders prefer halogen, older incancescent. Then, after all was said and done, every party stated they felt hairlines should not affect the grade or cost of coin. You and JeffB are right about light source, After that, I feel it's all relative. As it goes, I will check for hairlines (trying halogen).

 

These days, halogen lights are available in many intensities. I have a small desktop halogen that is less than 100 watts. It is SUPERB at showing hairlines -- even better than any incandescent I've used because it is a tiny bulb/point source (but, boy, it sure does get HOT). Perhaps the ANA comments were written before they were available?