leave the black? follow up question added...

[vacationchick]

This may sound weird, but I think this may look better leaving it as is...  Or in all of your opinions, would it look better if I attempted to scrape off all of the dark stuff?  I am assuming that the patina is the lighter brown?  

Once I get that part straightened out, I will probably be posting this to the id page as I can't seem to make sense of the letters.  I thought I saw an ons on the left side of the obverse and a tones on the right, but that doesn't come up with anything...

I hope no one minds the red backgrounds, I have been using black and I realized it was making the colors look terrible (silvery and washed out).  This looked much better to me.  Now in my spare time, I want to re-photograph all the old coins... Don't hold your breath...

Thanks so much for all your help!

[areich]

I don't mean to be rude but maybe you should read up on patina. The red is the metal, the black is patina. This coin looks like it never had a proper patina but in general, the aim is not to clean AE coins to the bare metal.

[vacationchick]

No offense taken, I am the first to admit that I am a newbie, but WOW!  I just can't win around here lately!

Glad I didn't scrub off the black and will leave it as is.

I have been doing some reading... here is a copy of one I recently read...

"The color of the patina on ancient bronze coins is usually green, and can range from very light green to a deep, lustrous, dark verdigris green. Sometimes patinas are seen in other colors, as well, such as blacks, reds, browns, and yellows."

Obviously, nothing beats experience, but can someone show me an example of the "red" patinas as I thought this could possibly be an example, but obviously not... 

[Syltorian]

https://www.forumancientcoins.com/board/index.php?topic=69027.0 and links to KC's gallery. 

[casata137ec]

Here is a "red" patina. And yes, stop where you are.


Chris

[renegade3220]

You are not going to find the red patina too often in comparison to a green patina. Leave this coin as is. I agree.that it doesn't look like it really ever had a proper patina. The bare metal and patina on this look like they are on the same level to me. I hope you didn't scrape down to the red areas, but if you did don't worry too much. It is a good learning lesson.

[SC]

The coin says CONSTAN-TINOPOLIS on the obverse and  BSIS in the reverse exergue (bottom).  There is nothing around the edge of the reverse.  It is a Constantinopolis coin issued 330-337 under Constantine I the Great, though it does not name him.  It commemorates the founding of Constantinople, on 11 May 330 AD.  It is from the second (Beta) officina (workshop) of the mint of Siscia (modern Sisak, Croatia).

Shawn

[vacationchick]

I REALLY appreciate everyone's help!  That "real" red patina is quite pretty...

I am quite glad that I didn't scrape anything on this coin... just a DW soak and very light brushing with a soft toothbrush.  I picked a small amount of dirt out of a section that is still black and this is what I got.  If I had scraped all of that, I would be kicking myself in the seat of the pants right now.  I still, personally, think it is a cool coin...who could not like a guy with a TOTALLY awesome hat like that    Also, thanks for the ID... I was going a bit crosseyed and it saves posting it again!

Since I am on a roll with stupid questions, I have one about patina that I have been trying to figure out...

On a previous post, someone gave great advice that the patina is the coin, not on the coin.  This totally made sense to me as it would be the top layer oxidizing.  It makes sense then, that if you scratch through that, you will find shiny metal below.   

What I am not understanding then is the coin that has the ?patina that you can "flick" off... like the coin I posted last week with that thick green stuff on it.  If you can flick it off, does that make it not a real patina?  In addition, when the stuff pops off, there is bare metal below, but it is not shiny (like on this coin), but I am sure if I were to scrape through it, it would be shiny (don't worry, I don't plan to try it).  Does that make it "toned" bare metal? a patina of sorts? Rust? 

Again, thanks for being so tolerant!

[casata137ec]

I REALLY appreciate everyone's help!  That "real" red patina is quite pretty...

...

What I am not understanding then is the coin that has the ?patina that you can "flick" off... like the coin I posted last week with that thick green stuff on it.  If you can flick it off, does that make it not a real patina?  In addition, when the stuff pops off, there is bare metal below, but it is not shiny (like on this coin), but I am sure if I were to scrape through it, it would be shiny (don't worry, I don't plan to try it).  Does that make it "toned" bare metal? a patina of sorts? Rust? 

That is the only "red patina" coin that I have and one of the most complete that I have seen (along with filling a Domitia hole in my collection! lol). I agree on the "pretty" comment!

OK...let me first state my non-expert status. Everything I write about on this particular forum is simply first hand experience, so I do not know the fancy names for things...with that said...

Yes, it is still a "patina" if you can flick it off. Generally speaking, if it is flaky, the flan has started to corrode and the adhesion is no longer as strong as once was. You will see that a bunch with (as in your example) thicker green coins (with powdery pink junk underneath a lot of the time). Patina is simply pretty corrosion in my eyes.  There are some coins (a lot of british dug uncleaneds are like this) in which the design you see in the patina is all that is left of the design, remove the patina and you remove the design leaving a slug. I figure that acidic soil plus moisture equal coins like that. "Desert" patina coinage is usually just impacted sand over a black coin (little moisture, neutral "soil" - fairly easy to clean and can be quite good looking). And there are a million variables in between.

The bare metal you see that is not shiny is, again, simply corroded. Just to a lesser extent.

As for how far to take a coin when cleaning...that is a judgement call. If you can make it pretty again without harming the coin, I say do it. Just remember, though, one slip of the hand can ruin a gem. The best tool in a coin cleaners arsenal is patience.


Chris

[vacationchick]

Thank you again for all of your help!  I guess learning what to do with each individual coin is the "art" of coin cleaning. If they were all the same, it would be easy to figure them out.... maybe...

[SC]

Like Chris I too am a non-expert.  I have no science background.  So this all comes from personal experience and what I have read.

First beware that almost all of us here throw the terms around somewhat loosely or use them in different fashions.  For example when people say "encrustations" that can include things that are clearly stuck ontoo a coin - hard dirt and cement-like sand and even small stones - and/or it can refer to thick, often porous stuff that is clearly the metal of the coin reacting with outside elements.

Basically anything that is due, at least in part, to the changes in the metal at the surface of the coin is a patina and anything that is foreign matter just stuck on is not patina.

One confusing issue is that a coin can have several different layers of patina.  It is not always a case of green over shiny metal.  It all depends on what environments the coin was exposed to and for how long, as well as the metal of the coin. 

For example you can have thick porous green crust over nice hard solid green patina over a dark brown patina over the shiny metal.  Or you can have a coin that looks the same but just has the thick porous green over shiny metal.  I have bronze coins that have had hard green "malachite" blobs over thin but very hard black over a fully intact silvering layer.  There seem to be an almost infinite number of variations.

Another confusing issue is that the line between what is part of the surface and what is just stuck on often blurs.  I usually clean using a 20x stereo microscope.  There are often coins that look in hand like they have dirt stuck on them but that under the microscope are clearly much more complex with the dirt "merging" into the metal corrosion.  (I am sure there are more technical terms for this.)

Shawn

[vacationchick]

Wow... this is so much more complex than "the top oxidized layer of a metal coin that has various colors"

I think I may have to go back to college for a degree in metallurgy

Thanks for everyones help, wish I could just "absorb" some experience through the net...

[casata137ec]

Wow... this is so much more complex than "the top oxidized layer of a metal coin that has various colors"

I think I may have to go back to college for a degree in metallurgy

Thanks for everyones help, wish I could just "absorb" some experience through the net...

lol...yeah, cleaning coins is not the easiest thing in the world to do, and a lot of people find that they just do not have the patience or even enough interest to continue this side of our hobby. The more you do it, the better you get, though. Every coin is a puzzle. Somtimes they come together as easy as pie, somtimes you can't find two edge pieces that fit!

Chris

PS and for that matter, this is a hobby I can do on my couch! so I from my couch, I can get my recently dug up buried treasure, tease out a coin, learn about an ancient emperor and possibly create an heirloom to pass down to my son! all while pretending to watch rachael maddow with my wife! you cant ask for more than that! 
C.

PPS and dont forget about a crash course in ancient latin and greek, chemistry, history, and specialized photography along with metallurgy!
c.