How to Tone Coins

How old is @BadThad, the chemist? How long has he been a professional numismatist as that may explain things. Say something long enough and change happens. Anyway, the Internet appears to agree with his definition at the moment as I have more research to do.

 

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The term you're looking for, or rather, the sort of expert you're looking for, is "metallurgist".

 

BadThad was a cad as a lad. Say that three times real fast.

 

Three ships slowly sinking........

 

I am sure he is much younger than either you or I. I would also venture he has been a "professional numismatist" ( studies coins and has made a name and money from his efforts) longer than you have been a professional chemist. I am curious why you found it necessary to bring his name in here.

I think everyone should slow down the argumentative mode before someone has deep regrets, and think before giffing or posting. Thanks. Jim

 

One of the members @ him! @ comments on dipping and cleaning threads and developed Verti-Care (but you know all that - right?).
We are having a discussion and it seems that the usage/meaning of certain descriptive adjectives has changed from the way they were used when I learned about the surface characteristics of coins in the past. I'm curious to know when this happened. That's why the age of @ matters. The change either took place before or after he came of age. The fact that he actually is a young professional numismatist who makes a living with coins lends more weight to his opinions as he may have helped change long held definitions of patina and verdigris.
Change is inevitable. Long ago coins were called "double dies." Decades ago the correct term "doubled die" replaced it. I already mentioned in the 1970's that the ANA taught "whizzing" was chemical cleaning. So now, I want to research the "change" that has taken place to "verdigris." @ may know something...that's all.

 

Edit

 

Thad posted twice in this thread and only used the word verdigris in one, just saying he saw little of it in the sample from a friend, nothing descriptive at all. We do have PM that can be used to directly ask questions (but you know all that - right?). Age has little to do with ones knowledge and profession. You can start a new thread on word definitions if you wish to research further, but lets try to keep it amiable. One or a couple of visuals such as gifs can enhance the emotion of a post, but excessive overuse can be an indication of aggressive posting, which I am sure is not your true desire. Thanks .

 

faces are so much fun and convey so much at the same time.

 

I'm no chemist. I am going to change my terminology based on posts in this thread and some recent Internet research.

I've learned that Verdigris is a "hard" encrustation of various chemical compositions in shades of blue and green that forms on copper or brass due to oxidation. It is also called "patina." So from now on, when I see the soft, green crud forming on the surface of copper (see Post#280) I will just call it "crud"

This appears to be one more case where the old teachings were incorrect and the younger, more informed numismatists corrected the record.
Thanks for the education

 

Dang!!! I wish I had said that.

 

You were too modest.

 

I knew I needed to add sometimes powder-like, etc., etc... to stay out of trouble.

 

Isn't corrosion describing the effect, and patina is the layer and color that forms?

And, maybe verdigris is a type of patina - one that easily falls off.

The dictionary definitions use "patina" in its description of verdigris.

So, isn't verdigris a layer that forms that easily falls off, whereas toning has a stronger bond?

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Doesn't that mean they are types of, from more general to more specific:

Corrosion > Patina > Verdigris & Toning

The above would be easier to see in a "tree-branch" diagram.

Is the above correct, below the dashed lines?

 

Only if you're someone who uses those terms that way. These are among the most ill-defined words in numismatics.

If you like the coin, it's patina and toning. If you don't, it's verdigris and corrosion.

 

I'll take a stab on this based on my new understanding.

Isn't corrosion describing the effect, and patina is the layer and color that forms? Corrosion, patina, verdigris, toning, etc. are all physical manifestations of oxidation. All of the above characteristics can be said to affect the surface (raised or into). However, they are usually regarded differently. Patina is often used to describe "pretty" corrosion. Just as tarnish is used to describe "ugly" toning. And, maybe verdigris is a type of patina - one that easily falls off. Apparently, verdigris is just another word for a similar product of oxidation. A quick look on the Internet shows objects with pretty verdigris and some that are just plain corrosion!
The dictionary definitions use "patina" in its description of verdigris.
True, the two words seem to be interchangeable. Nevertheless, I think "patina" conjures up something more "favorable."
So, isn't verdigris a layer that forms that easily falls off, whereas toning has a stronger bond? IMO, toning is a strong bond; however some forms of toning (color) will wipe off a surface. Patina or verdigris is also a strong bond as the metal is being destroyed at the point of contact. The fact that it can be powder-like on its top surface is just like more familiar rust. The metal has "brown colored rust (patina)" and in many cases the top layer can be rubbed off like a powder. NOW, patina or verdigris should not be used to describe a brown surface (as my example) as it refers to green and blue coloration. Sorry to add this: Right or wrong - glossy brown ancient coins have been described as having "patina."

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Doesn't that mean they are types of, from more general to more specific:
Corrosion > Patina > Verdigris & Toning
The above would be easier to see in a "tree-branch" diagram.
Is the above correct, below the dashed lines? I think rather than a progression they are technically all the same thing.

If there are no misstatements here, I think I finally "get it."

 

In the immortal words of Chico Marx. "If we look at it, it's a barn, if we smell it, it's a stable."