Has my coin been cleaned?

All true enough Doug. I could have been more technical with the explanation, especially regarding what comes first - the chicken or the egg (flow of the planchet metal or erosion of the die) - but I chose to simplify, as most people will not relate to flow lines they cannot and will not see on the first coins struck from new dies. They definitely exist, but are not readily apparent, even under significant magnification.

Regarding the "lessening of the luster", I'm not sure whether I agree or not. The reflective intensity per unit area certainly drops with subsequent strikes, however, the total reflective area increases as the surface of each subsequent coin becomes more deeply furrowed. Measuring the total reflectance of the surface of two coins struck many thousands of strikes apart with the same die, and measured under exactly the same lighting would likely tell the story.

 

Absolutely. Learning how to correctly identify harshly/improperly cleaned coins, in all their forms, is one of the most difficult things there is in numismatics.

But "fuzzy edges" ? I get your point but - nahhhhh. A coin has either been harshly cleaned or it hasn't - there are no fuzzy edges. Or, at the very least, that's how it is supposed to be, and always was for many, many, years - even among the TPGs, and long before the TPGs ever existed.

But I will grant you this much, that isn't how it is with them anymore. In today's world they routinely cleanly grade coins that they would have body bagged, back when they still had body bags. A single wipe was enough to body bag a coin, and that is how it should be.

 

Yup, it would. And what it will tell you is that this -

- isn't true. The total reflective area is decreased when the small and consistent flow lines are interspersed with the larger and inconsistent wear lines.

As I explained above, the key factor for high quality luster is consistency. Inconsistency lessens luster.

But I'll readily grant you Mike there are many who thought or even still think along the same lines as your comments - that wear lines increase luster. But by simply thinking it all the way through, logic and simply using your own eyes, and science if you wish to apply it and have the ability to do so, prove beyond a doubt that that isn't so.

 

Ehhh, I dunno. It was lack of education that let that genie out of the bottle, so it only stands to reason that increased education can put it back in

And I can give you two examples of where that's happened. 1 - for years, centuries even, harshly cleaning your coins by wiping them down with cloths and several other practices was the norm. But with education that genie was put back in the bottle. 2 - for many years the TPGs followed established grading standards and graded coins correctly. And then, lack of education on the part of collectors allowed them to pretty much start over-grading everything, and that genie was let out. But increased education has begun to put a stop to that, collectors in large numbers have begun to realize this, recognize it, and have become aware of just much and how badly the TPGs are over-grading coins. And that genie is well on its way to being put back into the bottle !

So yeah, it can happen. Escaped genies can be put back into their bottles But it takes work, effort, and a willingness to do so.

 

I believe it's education, and I'll tell ya why. I can remember back in 1960 when my grandfather, who first taught me about coins, explained to me that while it was the norm at the time for collectors to periodically get a rag or cloth out and wipe down their coins was a bad idea. He did that by showing me what doing that did to coins.

Now even at 7 years old I could see it, and what's more understand it. That's education !

 

Ahh, another subject on which we'll have to agree to disagree Doug.

Luster is a perceived quantity, as it is affected not only by material, surface finish and surface area, but also by the angle of incidence and the viewing angle. You can look at a coin with the light over your shoulder, and again with the light shining at the edge of the coin, and get entirely different perceptions of the coin's luster.

Luster is reflected light, measured in quantity of light (lumens), and not the intensity thereof (as in lux or lumens per meter squared). This is exemplified in our industry by distinctly separate references to the amount of luster and the intensity of luster on a coin's surface. If the total area of the reflective surface increases due to furrowing the surface, while the intensity per unit area decreases, there might well be no net gain or loss in total reflected light at all.

I am unaware of any conclusive research on a net reduction in total luster attributable to the erosion of coining dies, or other similar changes in surface finish.

 

We're saying much of the same things Mike but you're reaching a different conclusion than I am on the issue of wear lines reducing luster. And yes I agree with you that if viewing angles change, the amount of reflection changes.

And I agree that luster is a measurable quantity. But, if measured from the same viewing angle, the more consistent the flow lines (which are the reflective surfaces) the more luster there will be. As I mentioned earlier, this is proven beyond any doubt with Proof coins. Die wear absolutely reduces the amount of luster on Proof coins. (and I don't know of anyone who would dispute that)

And, it is also a fact that consistency increases reflectivity and inconsistency reduces reflectivity. Given that, and given that wear lines would absolutely decrease consistency, well, it must be so with business strikes as well.

 

THAT, Doug, is entirely a matter of perspective . . . literally. I am not saying that the amount of reflected light changes . . . I am saying that the total reflected light likely is the same, but distributed to different destinations.

If you look squarely at a proof coin, you can fully appreciate the quality of the luster, but viewing from the same angle robs you of the best view of the luster on a business strike.

Conversely, the most favorable angle from which the luster of a business strike may be viewed would substantially degrade the apparent luster of the proof coin, both coins exposed to the same light from the same point of origin.

Moreover, as regards your assertion that "Die wear absolutely reduces the amount of luster on Proof coins", die wear certainly converts luster on proof coins, but I'm not convinced die wear necessarily reduces luster.

Consider the isolated case of some 1953 proof Franklin half dollars struck late on a particular die pair, which look so much like business strikes that they are often submitted for superb mint state grades. I have one of these in my SDB from decades ago. Were it not for knowing what a proof looks like at the rim, I'd have submitted that coin with the same goal in mind. That coin is a great example of how proof luster migrated from being an incredibly deep mirror finish to the tantalizing cartwheel luster usually reserved for business strikes.

Another example of luster conversion involves the devices of cameo proofs. While heavily frosted at the onset, erosion of the dies eventually mutes the frost and converts it to a deep brilliant mirror finish. This, all by itself, is evidence that the erosion of the dies does not substantially impair the reflectivity of the surfaces, but it does change the direction in which the light is reflected.

I cannot help it if the evidence doesn't convince you Doug, but I remain steadfast in my belief in what I'd label as "conservation of luster" (akin to conservation of momentum or conservation of energy in physics), were it not for the potential confused use of the word conservation in this industry.

Respectfully,

- Mike