Patina Is Good

[wolfgang336]

For those of you who are new to the art of cleaning coins, allow me to give you the most important pointer there is in this field:

Keep the Patina intact!!

1) The coin will be worth more
2) It protects the coin from Bronze Disease
3) Confirms authenticity
4) You won't kick yourself when you're a more senior collector

Happy Cleaning, Evan  

[newbeonecoinobe]

Patina Is Good??,  You hear this all the time but why does it apply more to bronze and copper than it does to silver.  I realize that sometimes when you clean a coin just so you can Idenitfy it some of the patina comes off, but a lot of the silver coins you see have been cleaned down to the shinny silver and that seems to be fine with everyone.  Also the larger old coins 1st and 2nd century you see on websites and ebay for sale all look like they have been cleaned down to the base metal?  So if you have a large copper or bronze that you can just barely make attribution on should you leave it like that or bring it down to the point where you can actually see the coin?  The next obvious question is why does this appear to be different when dealing with a silver coin?

Thanks
Pete

[wolfgang336]

Silver doesn't get a patina. It tones over a large amount of time, but some dealers prefer to remove the toning to make it shinier. This isn't necessarily good, but it's not as bad as removing the patina from a bronze or copper coin, because over time, or with some help from a few things you have around the house, it can regenerate.

As for big coins: These are no different than little coins, the patina should be kept intact at all costs. It is very rare that a patina obstructs the coin's devices from being identified. The big coins you see on eBay that have already been taken down to the bronze have been improperly cleaned, and yield nothing that you couldn't see on the coin before in all likelyhood.

Evan

[Robert_Brenchley]

Very often the detail is in the patina, which can often preserve the riginal surface of the coin. Remove it, and you tend to be left with a nasty pitted mess, which lacks detail. Even when its not as bad as this, a depatinated coin almost always has some pitting, and an unattracftive surface. Of the several hundred coins I've cleaned, I've only come across one which was improved by removing the patina. I just wish I had a 'before' pic, it would be a real object lesson in what a nasty patina can be! But its a rare situation. 99.9% of the time, patina should be preserved.

[meroettger]

Is a patina necessary to confirm authenticity?  E.g., if I sent the coin for authentication, would having it scrubbed clean prevent it from being labeled as the genuine specimen?  

Also, how much of the patina is intrinsically valued?  I am thinkng, for instance, of some valuable US pennies where the shiny mint luster may make them worth more than a coin which has been allowed to form its patina by perhaps just being exposed to air for 100 years.  What about a patina is a norm/value for ancient Roman collectors, and what is necessary?  A related question might be, how much does keeping the attractive patina on add to the value of the coin [economic and personal value]?

Those are just some thoughts that pop into my head when I ask myself "Why keep the patina?"  Especially, when the coin was likely new and shiny 2000 years ago.

I say this having stripped a few coins to the bare, shiny bronze and felt it greatly hurt the coin's appearance.  I would much rather underclean a coin that "overclean" it, but have wondered if this is more a function of taste and a desire for conservation than anything else.  


Thanks,

Michael

[Joe Sermarini]

A patina is not necessary to confirm authenticity, but it can help.  

Museums and archeologists will often strip coins of their patina.  They sometimes see coins as artifacts that should be returned as close as possible to their original state.

Collectors also see coins as artworks.  Collectors appreciate the beauty of the coins, not just the historical aspects of them.  Sometimes these miniature artworks have been aged by nature with very attractive results.  A patina is valued because it looks nice.  The price of a coin is increased by an attractive patina.  A beautiful patina can increase the value 10 times.  Stripping the patina off of a common coin can make it worthless.  

[Robert_Brenchley]

Stripping patina doesn't return a coin to its original state at all! What it does is reduce it to whatever is left of the bare metal, which isn't the same thing. The overwhelming majority of ancient AE's have undergone some degree of corrosion, the metal from which has often gone to form the patina. There's no way of returning it to its original, uncorroded state, as it was when it was lost or buried. I can't help suspecting that they often strip coins because the manhours to clean them as we'd all like it done just aren't there.

[TreyAlbers]

OK, but what if your coin has no patina to start with?

I have an AE3 that I received in an uncleaned lot, which had what appeared to be two small patches of black-gray patina, one on the portrait, and one covering a few letters of the legend on the reverse. The rest of the coin was just encrusted with loose dirt that brushed off easily, down to the bare metal, after a good soaking in olive oil.  

For aesthetic reasons, I tried to remove the partial patination with a brass brush, but it has proved stubborn, and now looks like it could be partial silvering (dull, metalic gray, like old pewter).

Now I am wondering if I have made a mistake.

Here's the coin:
obverse: IVL CRISPVS NOB C, laureate, draped & cuirassed rt.
reverse: CAESARVM NOSTRORVM, VOT . V in wreath, T (star in crescent) A in ex.

Any advice would be greatly appreciated.

[basemetal]

mmm...patina is good...ok..here I go....
I've read the posts extensively...from what I can tell it's the cultural norm here that "patina is good". Disagreeing about this is the one way to earn the animosity of otherwise helpful and fine folks.
Newbie gets this:
...everybody knows patina is good because....
most assume you are either going to sell the coin at some future date .....or it shows the age of the coin....or it's attractive.....or it hides pits....or you can "damage" the coin by removing patina.
"Damage" is a subjective term.  I've seen so many posts that say "Well...ya musems do it cause"
but to the "serious" collector patina is everything or at least a lot. It shows the "age" of the coin. Hey...it's roman coins we are dealing with here we know they are of a certian date....if your auntie expects a roman coing to look "old" ok then. We already know the age.
It's Attractive: Well...again subjective..I like seeing all the details...again see above..I never plan to sell any coin I get.
You can "damage" the coin.  With the exception of zapping a silver coin...and that's the one legitimate  argument in my opinion ....how exactly?....well..you will destroy the patina..ahem..we are going in circles here...
 You may want to keep the coin without ever selling it...most coins I see on here aren't exactly the get rich quick thru sale kind-I personally plan to keep all the coins I get.  I like to see alll..the details.
Patina is "attractive"...mmm...subjective. That's why modern furniture is "distressed" which means scratches and dings are introduced at the factory. Again.If you like it go for it.
You are preserving history by leaving patina:
Well....you took off the crud...didn't you?  By olive oil..or whatever....the logical extension would be...buy uncleaned lots...display 'em... .hey authentic roman coins just as they came out of the ground.
No collector in his/her right mind would clean a priceless artifact in any way ....these are "god's coins"
just like they came out of the ground.
My personal opinion is that it's a personal choice and the only downside I see to the forum..which I love and has been good to me is the entitlement attitude "Well...everyboyd knows that you preserve the patina"  argument.
I anticipate the moderators revoking my membership. But I'll still lurk and learn.

[wolfgang336]

We're not about to delete your post, so you can sit easy.

Well...again subjective..I like seeing all the details...again see above..I never plan to sell any coin I get.

That's well and good, but the patina actually is the detail in many cases. Remove that, and you may strip the coin of most of its detail.

How would you go about removing the patina? It is not the fact that it is gone that damages the coin (although that is also true, see below), but how the patina comes to be stripped. Gouging at it will leave horrible marks, and you may end up inadvertantly tooling it.

The removal of the patina also opens the coin up for attack by bronze disease. The oxidization almost seals the metal in from moisture, and without it, such fragile metal is soon to degrade.

You may also believe that you will never sell any of your coins. Trust me, it won't last. As your collections becomes more focussed, you'll be forced to sell to finance your newest additions.

Well....you took off the crud...didn't you?

Some people follow this line of thought, and preserve the coin as it comes out of the ground. However, when a good cleaner cleans a coin, he knows that the patina is a result of a reaction with the metal of the coin, therefore the patina is part of the coin, while the dirt is not.

Here's an example from the gallery, from the collection of our very own Heather. I'm certain this coin looks better with its patina than it would without, wouldn't you agree?



Regards,

Evan

[exquisiteoaf]

I am a very novice collector, but i'm pretty sure this is an extreme example of the occurrence of scrubbing off patina and losing the detail in the process.

The coin, I believe from my amateur attribution efforts, is a Constantius II bronze with the emperor/victory steering galley reverse type.

Originally the coin was covered in a smooth green surface, more or less. It belonged to a friend of mine who has since passed away. He recieved it in a lot of uncleaned coins. He had soaked it in olive oil for a while (maybe a week or two?) then gently taken a brass brush to it...the results are shown in their full hideous glory. The supposed surface of the coin, showing quite good detail, actually started coming off in chunks almost like it was clay or something.

If i'm correct, this should illustrate that patina sometimes IS what's left of ths surface detail. Thoughts anyone?

Thanks,

Mike

[stickman]

If i'm correct, this should illustrate that patina sometimes IS what's left of ths surface detail. Thoughts anyone?

You are correct!  Although this is an extreme example it does show that some if not all of the detail can be in the patina.  I've been meaning to post a photo showing that, but now there is no need, you have posted a perfect example.

[exquisiteoaf]

I'm glad to help on this. The coin was just screaming out to be shown as an example. This was from the days when me and my friend were just starting with uncleaned coins and had no idea what we were doing. We thought we were seeing things when the detail started coming off in chunks like that, but it does happen.

Mike

[Rebekah S]

Hi,

This may be a judgment call: I've just met a collector whose ancient silvers were stored in velvet trays on non-archival paper, and he's been handling them as well. They've darkened over the last 3 years, and he wonders whether to leave them as they are or polish them. He does not plan on selling the collection but wants to donate them ultimately to an academic department or museum.  Will one polishing to remove 3-year darkening destroy the surface toning? Should he leave them alone?

Thanks,
Rebekah

[Robert_Brenchley]

Silver darkens; it's reactice stuff, hence its use in photography, and it combines with oxygen. It's called cabinet toning, and it's usually considered to add to the coin, rather than detracting from it. They should never be polished, if the effects ever go away at all, it takes many years. I curse the person who polished one of my silvers every time I take it out of its flip! They should let well alone.

[basemetal]

Wow!  For those of you newbies like me....go back and read my post of...November 24 or thereabouts of last year.  My ears turned red just now.   
What a bunch of overblown hooey I spouted!  Clean 'em all!....I said in my ignorance. 
If you are new to something which has been going on for literally centuries, meaning ancient coin collecting, go with the experts and those experienced in the field. 
In the interim I have learned or acquired something I suspect is true about stripping patina off coins, that we newbies so like to do.
I think some of what the desire to strip coins comes from is ...let me see...If I can articulate this correctly.  A collector wants to know what a coin's attribution is.  He/She assumes that removing encrustations which we newbies  in the beginning of collecting includes patina, will help in attribution, and though we don't dare say it, increase the value of that "rare" coin you've found or think you've found. Nope.
I have a pretty nice though worn Trajan with the famous Danube bridge reverese. Big, thick heavy 33mm Sestertius.   You see them sold for muyo money on various sales venues.   Well, mine looks at first glance like pure gold-that's how cleaned it is.  I didn't do it.  I bought it that way.  It's worth-whatever someone is willing to pay.  Meaning not much since it's as shiny as  a new trumpet.  Yes, it's original, and yes, there are sufficient details showing to make it worth a little to someone who just "wants to own a roman coin"  but now that it's cleaned like that, it's a curiousity, nothing more. With the original patina, which I feel sure was a nice green, it would be both displayable and sellable. Not now, however.
I think one factor that I haven't seen mentioned is the illusion that patina is covering up details that are in fact simple wear.  A worn coin looks much like the detail has been smoothed over or covered with "something". Often that something which is patina, gets removed in the quest for more detail.
The details you do not see are gone.  Face it.  Gone.  They wore away 1800 or 1900 years ago and are simply not there or corrosion has removed them.  They can't be put back. 
Yes, you can "tool" a coin by using modern engraving instruments to bring out lost detail, but  why not just add your initials while you are at it?  It's not an original coin anymore.
Patina comes from the original material of the coin and to use a metaphor is like the wrinkles an aged face has. The wrinkes got there honestly by simply surviving over time.  A 50 year old actor who has had extensive plastic surgery does not fool movie agents  get parts suited for a 25 year old actor-tho like newbies like me some try.
A "face-lifted" coin doesn't become a Very Fine specimen just because the oxidation of the ages has been removed.

[Robert_Brenchley]

We've all been there; no need to feel bad about it.

[Rebekah S]

Hi, All,

Thanks for the input. The collector I'm talking to was concerned because the darkening happened so quickly. I've advised him to get the silvers off the paper they were sitting on. *Since he has been handling them,* should he give them a wipe w/ a clean cotton cloth to remove any remaining oil, or not even that?

Rebekah

[Robert_Brenchley]

How quickly is quickly? I have a denarius that's toned nicely in three years, just sitting in it's flip. That's a lot faster than I'd expected.

[dpaul7]

HI all --

Just my 2 denarii worth --

THANKS to exquisiteoaf for his excellent post! I received a nice lot of mixed coins recently.... cheap... listed as not good quality.  Well, a couple great coins came out of that batch!  Some were only pieces of coins... yet beautiful, and identifiable.

BUT -- In addition to the GREAT practice I got CLEANING the coins (even though some didn't have too much there....) I saw about 4 examples of what exquisiteoaf illustrated.... A coin that was TRULY BEAUTIFUL -- except that one portion of the surface patina was missing... and the detail underneath was only a "ghost" of the original image.  I don't know why certain coins will "flake away" like a piece of old slate.... probablly the conditions the coin came from.  One damaged piece like this was my experiment -  Yes... with aggressive manual cleaning, you WILL lose more of the coin. Some just peel away!

I guess the best way to deal with it is to soak, brush with a toothbrush and then find some way to seal the coin.

dpaul7

[Cleisthenes]

Joe Sermarini says beautiful patina can increase a coin's value ten fold; Robert Brenchley says keeping a coin's patina is beneficial 99.9% of the time, and Evan (wolfgang336) recommends keeping patina at all costs.  If three experts agree--that's pretty good triangulation!  Keep the patina.

Jim

[Runelord]

I was in Rome recently, talking to a coin dealer, and apparently there are some coins that are discovered without a patina.  (I was recently surprised by this, but, really it makes sense that, say, a coin that's found in the Tiber river in or near Rome would have no patina).  It was actually rather interesting to see a bronze coin without a patina: it was a much lighter and more yellow color than I thought it would be.  Although I would never mistake it for 'gold' like do with patina-stripped bronze coins, I could definitely see why some new collectors (yes, I am, in fact, obviously a new collectior as well) would think their bronze coin without a patina may be some gold alloy (orichalcum, or something similar) if they had not seen such coins before.

Just my 2c about an interesting personal discovery,
Runelord

[slokind]

True about Tiber coins, given the right conditions.
False about the etymology of ori-, which derives from the Greek word for mountain and has nothing to do with the Spanish and Italian words for gold.  The legend about orichalcum was that it was found naturally in some mountains in Asia Minor.  It is brass, about 80% copper.
Confusing or- with aur- is folk etymology, such as when modern Greeks who weren't very attentive in school mix up skênê (from word for tent) and schoini (word for rope), now pronounced alike by most, and don't know whether Paul of Tarsus was a tentmaker or a ropemaker!
Pat L.

[Cleisthenes]

. . .  I could definitely see why some new collectors (yes, I am, in fact, obviously a new collectior as well) would think their bronze coin without a patina may be some gold alloy (orichalcum, or something similar) if they had not seen such coins before.

Just my 2c about an interesting personal discovery,
Runelord

Perhaps it was electrum that you had in mind?  Electrum is an amber-colored (sort of ), naturally occurring alloy of gold and silver used in ancient times.  At least the earliest coins were made of the natural alloy.

Jim (Cleisthenes)   

[slokind]

I very carefully avoided speculation (and called the stories 'legend') as to what might lie behind the texts.  In this I follow the exccellent example of Caley, Earle R., Orichalcum and Related Ancient Alloys, ANS, Numismatic Notes and Monographs, no. 151, 1964.  Caley was a well trained experimental scientist.  He respects but does not reprehensibly exploit what Strabo got from earlier, lost sources (see Caley, op. cit., pp. 18-31; the Strabo reference is Geography Book XIII, sec. 56.  If you use the Loeb, remember that the translator may not have been a metallurgist or anything like one).  So much for the zinc.  The mention of oreichalkos is in the poem Shield of Herakles, which you find among the 'Homeric Hymns'.
We now know more about the extraction of metallic zinc in earlier antiquity, but in Asia Minor that was so early that it doesn't affect Caley's discussion, apart from qualifying how little we know about the beginnings for zinc.
Note that Caley is at pains to provide a close translation of his own.  Though not a Classicist, he is not content to take anything on authority without going to the sources and carefully considering them all, both textual and archaeological and metallurgical.
We just can't be tempted by understandable jealousy of the way that Renaissance men could make spontaneous surmises.  Those days are gone forever.
Pat L.