Do you think it would be technically possible to repair/replace luster?

[Prethen]

I don't think I've seen any serious discourse on this topic and maybe I missed it somewhere, but I'm very curious to know if this is remotely feasible.

Look, it's just physics! LOL

Of course, I'm not talking about whizzing here...which is simply just destroying a coins surface to get a sort-of lustrous effect.

Assume the coin in question is a super choice AU seated quarter that has been over-dipped and "stripped" of its luster.

I realize that luster is essentially light reflecting off of the coins microscopic, radial lines produced when the dies strike the metal (and I apologize if my description is not quite accurate). But, I could imagine that someone has invented or could invent a technique where you could subject a coin to some process where the fields are exposed to some element or stress or whatever in a radial fashion (while not disturbing the devices) to reproduce the missing "luster" where it could be virtually undetectable to the professional numismatist.

And, if such a technique does not currently exist, I got to imagine it's a matter of time before it becomes in the realm of possibility.

[Just Bob]

Interesting question. We already know that low level radiation won't do it. I wonder if lasers are capable of doing that kind of sub-microscopic (if that is an actual  word) work. As you said, the trick will be to make it undetectable, possibly by making the alterations so tiny that it doesn't show under high magnification. Or, by mimicking the original surface so perfectly that no one can tell the difference.

[JKK]

It is my understanding that the way the flow lines develop has a lot to do with the raised points, which provide varying topography of course. I'm not sure how one would simulate the authenticity of that effect. I mean, it would be one thing to restore them on a theoretical coin whose devices consisted of a single concentric dot/circle. On a normal real-world coin? I can imagine it being very challenging to achieve there.

[Six Mile Rick]

You can bring the luster out that is still on a coin with preservation. You can't replace luster that is forever gone without damaging the coin.

[numisport]

It would need to be re-struck

[grip]

15 hours ago, numisport said:

It would need to be re-struck

I agree!

[coinman1794]

Yes, the only way to replace luster would be do re-strike a coin. By definition, any such attempt would constitute damage.

I know some fantasy coins are made by over-striking a similar design atop an existing coin. Short of something like that, there is no replacing luster.

[Prethen]

I have to wonder if there isn't a high-tech alternative. I would think that maybe it's possible with a combination of lasers and decent AI. There might be a materials expert here to correct me on this, but I believe those flow lines are nothing but a bunch of radially spread micro crevasses. For the record, I'm not advocating that this ever actually be done, this is more of an academic exercise. However, it might be worth thinking about in case the technology does become more advanced and inexpensive. It would be pretty amusing to see a fully lustrous coin in Good condition, huh?

[Conder101]

You know it just might be possible, but it would be time consuming.  You would probably have to be able to engrave lines just a few angstroms apart (And probably just an angstrom or two deep) radially all the way around the coin from the center to the edge.  If you make them about 10 angstroms apart your talking maybe 600,000 engraved lines on a coin about the size of a cent.  But you probably wouldn't want all the lines to go all the way to the center, you'd burn it out.  So you would want to stagger the length of your lines.

[numisport]

7 hours ago, Conder101 said:

You know it just might be possible, but it would be time consuming.  You would probably have to be able to engrave lines just a few angstroms apart (And probably just an angstrom or two deep) radially all the way around the coin from the center to the edge.  If you make them about 10 angstroms apart your talking maybe 600,000 engraved lines on a coin about the size of a cent.  But you probably wouldn't want all the lines to go all the way to the center, you'd burn it out.  So you would want to stagger the length of your lines.

I like your theory but it would be way too tough to know where these lines would start and stop to create real life light reflection we perceive as luster.

[cladking]

On ‎10‎/‎19‎/‎2018 at 10:10 PM, coinman1794 said:

Yes, the only way to replace luster would be do re-strike a coin. By definition, any such attempt would constitute damage.

I know some fantasy coins are made by over-striking a similar design atop an existing coin. Short of something like that, there is no replacing luster.

I'm in close agreement.

No doubt techniques could be invented to fool a quick glance or the novice but I believe it would leave tool marks that show up pretty dramatically under the lens of an expert. 

[Prethen]

I would assume that the experts could be fooled if the luster was applied by using AI applied algorithms which exactly mimic what would be seen on a freshly struck coin. The techniques for doing this would be complex and take a lot of trial and error, but I would think it's in the realm of possibility.

[cladking]

3 hours ago, Prethen said:

I would assume that the experts could be fooled if the luster was applied by using AI applied algorithms which exactly mimic what would be seen on a freshly struck coin. The techniques for doing this would be complex and take a lot of trial and error, but I would think it's in the realm of possibility.

I believe it's much too complex for current imaging devices. 

Computers are still effectively "blind".

 

 

[Prethen]

19 hours ago, cladking said:

I believe it's much too complex for current imaging devices. 

Computers are still effectively "blind".

 

 

Not as much as you think anymore. Yes, there's a ways to go, but the object recognition technology is getting exponentially better each year. Recognizing raised devices on a coin...I think that is already in today's realm of computational possibility.

[LINCOLNMAN]

If it becomes possible, Chinese coiners will likely be the first. However, the supply of valuable coins that would have sufficient meat on the bone to pass muster might be a limiting factor.