The Fingerprint Discussion

I hate those nasty little prints on coins. Nothing turns me off to a coin faster than a print. However, I have some questions: I understand prints on coins are a result from a chemical transition of the oil from one's skin to the metalic surface of a coin. I also understand, that if found soon enough after the application of the print, an acetone dip may allieviate the effects the print may have. However, here are a couple additional questions:

1.) Can the oil of a finger bleed through the film of a 2X2 to be left on a coin?

2.) Once a print is on a coin, can the effects of that print worse over time? (Become darker, distort the tone, widen to include the total surface of the obverse/reverse? etc.)

3.) Why are prints more prevelant on mint-state/proof coins though their effects seemed dimished or not present at all when examining circulated examples?

4.) Is there a general time from which an acetone dip would not help a coin with a print? I imagine this is once the oil dries onto the surface of the coin?


Well, that should work for a nice print discussion. Thanks for answering the questions.

 

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1. No. Mylar is not permeable. It's a plastic film. Same thing used in roasting bags, which don't leak as well.
2. Yes.
3. Because the surface of a proof/ms coin is smoother. A rougher surface from a circulated coin wont allow the print to come in contact fully with the surface.
4. About one week.

 

because the MS or proof coins has nothing on it's surface. Then here comes the fingerprint. And that print tones and etches itself into the surface. There is nothing else around that print and so it stands out.

Now on the circulated coin it has fingerprints all over it. Every tiny spot on it's surface has the skin oils, sweat and salt on it and it is a pretty even coating on the whole coin. Since it is even, the whole coin tones at the same rate and none of the prints stand out from the others or the surfaces.