A dipping experiment
BryceM
Posts: 11,857 ✭✭✭✭✭
So, You might have been following this thread.
I decided to do a little experiement to see the effect of dipping over time. To do this, I set up my camera and copy stand and locked everything in place. I set the focus using tethering software and tried to position the coin in the same place and at the same rotation for each shot. I wasn't perfect at this, but decently close. ISO was set for 200, aperature at f/6.3, and shutter speed at 1/2000. Unfortunately, a few iterations in, the camera changed to 1/2500 which affects the final results a bit as you can see.
I used a can of EZ-est that I had laying around. It was opened several months ago and has been used previously for maybe a half-dozen coins. I make no pretense of doing this experiment perfectly! The coin was held in a pair of tongs by the rim and dunked for the time described. During the time of the soak, the coin was swished around. After the 5 minute point I gave up on the swishing action and just let it sit in the dip bucket with an occasional scientific jiggle. I then plucked it out and rinsed it under warm, soft tapwater for several seconds. It was then blotted dry with a clean towel and photographed. The times on the photos are cumulative total dip time.
The coin is one that I got in a "BU Peace Dollar Roll" from eBay. It has some issues which would keep it in the MS60-62 range. It was brilliant white to start with except for a funny deep toning stripe diagonally through "O" in "DOLLAR".
I got bored around the 30 minute point and quit. I didn't see much point in going further since virtually no serious numismatic coin on earth would see a dip vat for that long.
My observations:
1) The coin gets slightly darker overall (less reflective?) during the process.
2) The dark toning stripe at the "O" in "DOLLAR" lightens during the entire process, but is still present at 30 minutes.
3) Between 15 and 30 minutes a dark stripe has formed around "I" in "LIBERTY". I can't explain this - maybe it's from the rubber-tipped tongs or maybe it's my poor dip rinse?
4) I think I can see some diminished luster as time progresses. This is perhaps noticable comparing 15 and 30 minutes.
5) In hand, the coin is still lusterous after a 30 minute dip. It still has a great cartwheel effect and I'd be perfectly happy buying it as a "BU Peace Dollar".
6) The impact on the coin's luster is pretty minimal through the first 15 minutes. In-hand I could detect no difference.
7) The mirrors, if you want to call them that, get hazy as time passes.
Lest you think I used innefective or dilute dip, I followed up by dipping this 1922-P coin, which I plucked out of an old album several months ago:
This coin had some pretty good toning going on before the dip, but I selected it because I could see good luster under the toning.
1) Hits and hairlines are easier to see - no surprise.
2) The coin is still lusterous and it's much easier to see the depth and intensity of the luster.
3) Subjectively, it's prettier to me than in its pre-dip state
4) The blotchy toning around "TRVST" is gone
5) The spot between "9" and "2" in the date is mostly gone
6) The dark toning around 4 o'clock on the reverse rim is improved, but still visible
7) The toning stripe through "UNITED" is improved, but still visible
8) The rather dark spot between "L" and "I" in "LIBERTY" is improved, but still there
From this very small sample I've concluded that repeated dipipngs up to 5 or 15 minutes in total duration do very little to impair a coin's luster. There might be some loss of luster when total dipping times increase beyond that.
I would still like to explore the hypothesis that the formation of toning does more to impair luster than the process of dipping it away once formed.
If I get a rainy Saturday, I might take a lusterous coin, subject it to some medium-intensity artificial toning, dip it for 15 seconds, and repeat the process to a total dip time of 5-10 mintues. I'll also dip a control coin which receives no AT. In my mind, it's possible that molecular damage from the chemical reactions that take place during toning might be as damaging or even significantly more damaging than the process of simply dipping the coin.
"Over-dipped" might be more correctly stated "Over-corroded"
I decided to do a little experiement to see the effect of dipping over time. To do this, I set up my camera and copy stand and locked everything in place. I set the focus using tethering software and tried to position the coin in the same place and at the same rotation for each shot. I wasn't perfect at this, but decently close. ISO was set for 200, aperature at f/6.3, and shutter speed at 1/2000. Unfortunately, a few iterations in, the camera changed to 1/2500 which affects the final results a bit as you can see.
I used a can of EZ-est that I had laying around. It was opened several months ago and has been used previously for maybe a half-dozen coins. I make no pretense of doing this experiment perfectly! The coin was held in a pair of tongs by the rim and dunked for the time described. During the time of the soak, the coin was swished around. After the 5 minute point I gave up on the swishing action and just let it sit in the dip bucket with an occasional scientific jiggle. I then plucked it out and rinsed it under warm, soft tapwater for several seconds. It was then blotted dry with a clean towel and photographed. The times on the photos are cumulative total dip time.
The coin is one that I got in a "BU Peace Dollar Roll" from eBay. It has some issues which would keep it in the MS60-62 range. It was brilliant white to start with except for a funny deep toning stripe diagonally through "O" in "DOLLAR".
I got bored around the 30 minute point and quit. I didn't see much point in going further since virtually no serious numismatic coin on earth would see a dip vat for that long.
My observations:
1) The coin gets slightly darker overall (less reflective?) during the process.
2) The dark toning stripe at the "O" in "DOLLAR" lightens during the entire process, but is still present at 30 minutes.
3) Between 15 and 30 minutes a dark stripe has formed around "I" in "LIBERTY". I can't explain this - maybe it's from the rubber-tipped tongs or maybe it's my poor dip rinse?
4) I think I can see some diminished luster as time progresses. This is perhaps noticable comparing 15 and 30 minutes.
5) In hand, the coin is still lusterous after a 30 minute dip. It still has a great cartwheel effect and I'd be perfectly happy buying it as a "BU Peace Dollar".
6) The impact on the coin's luster is pretty minimal through the first 15 minutes. In-hand I could detect no difference.
7) The mirrors, if you want to call them that, get hazy as time passes.
Lest you think I used innefective or dilute dip, I followed up by dipping this 1922-P coin, which I plucked out of an old album several months ago:
This coin had some pretty good toning going on before the dip, but I selected it because I could see good luster under the toning.
1) Hits and hairlines are easier to see - no surprise.
2) The coin is still lusterous and it's much easier to see the depth and intensity of the luster.
3) Subjectively, it's prettier to me than in its pre-dip state
4) The blotchy toning around "TRVST" is gone
5) The spot between "9" and "2" in the date is mostly gone
6) The dark toning around 4 o'clock on the reverse rim is improved, but still visible
7) The toning stripe through "UNITED" is improved, but still visible
8) The rather dark spot between "L" and "I" in "LIBERTY" is improved, but still there
From this very small sample I've concluded that repeated dipipngs up to 5 or 15 minutes in total duration do very little to impair a coin's luster. There might be some loss of luster when total dipping times increase beyond that.
I would still like to explore the hypothesis that the formation of toning does more to impair luster than the process of dipping it away once formed.
If I get a rainy Saturday, I might take a lusterous coin, subject it to some medium-intensity artificial toning, dip it for 15 seconds, and repeat the process to a total dip time of 5-10 mintues. I'll also dip a control coin which receives no AT. In my mind, it's possible that molecular damage from the chemical reactions that take place during toning might be as damaging or even significantly more damaging than the process of simply dipping the coin.
"Over-dipped" might be more correctly stated "Over-corroded"
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Comments
I guess next time I won't have to scream bloody murder if I lose grip of the coin while dipping it.
Cool experiment!
Rob
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Thanks for taking the time for this! A good subject!
Eric
Best wishes,
Eric
U.S. Type Set
Now if I can get everyone to use the 15-30 minute method on all their similar rare dated coins that I also own, mine should increase greatly!
And that lighting is not helping matters I think.
Confirms my experience and thoughts on the subject.
Thanks for the efforts and sharing of the findings...
Dipping is something I very rarely do and only after careful considerations.
Happy, humble, honored and proud recipient of the “You Suck” award 10/22/2014
I'll be happy to change the lighting or photograph the coin any way you'd like. I'll even send it to the photographer of your choice for comparison views. I'm tellin' ya, in-had the thing still looks acceptable BU after a half-hour in the dip bucket. I'm not saying every coin will respond exactly the same way, but this one did. There are some issues I can see showing up at 30 minutes, but they're not terrible...... yet. I'm not in a big hurry to ruin coins - just thought it would be interesting.
<< <i>Wabbit,
I'll be happy to change the lighting or photograph the coin any way you'd like. I'll even send it to the photographer of your choice for comparison views. I'm tellin' ya, in-had the thing still looks acceptable BU after a half-hour in the dip bucket. I'm not saying every coin will respond exactly the same way, but this one did. There are some issues I can see showing up at 30 minutes, but they're not terrible...... yet. I'm not in a big hurry to ruin coins - just thought it would be interesting. >>
No worries. I am surprised there is not a white haze that looks like powder on it. Throw a Morgan in there for 30 minutes! Cheers!
My icon IS my coin. It is a gem 1949 FBL Franklin.
This excellent experiment and report support my experience with ugly toned Ikes and SBA's: one has to walk away and have a meal before there is any noticeable change on close inspection.
Overnight is a different matter, funny things can happen.
I ran a quick and dirty experiment with an Ike proof, and I thought there was loss of pure mirror (to the extent any Ike proof has a pure mirror, LOL) after a couple of minutes.
In my experience, "natural" toning that occurs over many months to several decades (ie, Ikes) is easily dipped off, but speedy intentional toning (for profit) can be difficult or impossible to dip off. My guess is purposeful heat is the villain though the hearty crust developed by some classic coins over many decades can bedifficult to remove, hence the coin cowboy's use of industrial strength dips, damn then.
I'm not concerned much about using the same jar of dip: the key with EZest is a nice light blue that's not "washed out" (sorry!). MS70 is better used with a Q-tip and a gentle rolling-swab motion.
In either case, thorough rinsing is THE critical step when dipping to conserve a coin.
Rob
Questions about Ikes? Go to The IKE GROUP WEB SITE
of the 1922 Peace Dollar but have never dipped. That coin looks better after dipping.
It would be interesting to take 2 coins in the "before" condition and dip one but not the
other and observe them over the years.
<< <i>Excellent experiment. I have numerous coins with the appearance of the "before" picture
of the 1922 Peace Dollar but have never dipped. That coin looks better after dipping.
It would be interesting to take 2 coins in the "before" condition and dip one but not the
other and observe them over the years. >>
Gotta say, probably shouting up from the minority, I prefer the before '22. Am I alone? It looked honest and had character. Not like oh so any others. But, not so the after pic IMHO.
Eric
1. the coin was dulled by the dipping which impaired the luster; it is up to the viewer to decide at what point in time that occurred.
2. from my experience I have rarely dipped a coin for more than 5-10 seconds at any one time.
3. as already discussed, the choice of which coins can be helped is critical. normally after the first dip or two, when no change took place with the tone stripe, the process for me would have stopped(though I would never have tried this coin to begin with).
4. to my eyes and judging the picture only, I notice a difference at the seven second mark with the coin starting to dull.
-----I think the real danger with coins like this comes when we tell ourselves that nothing is happening to the surface, as judged by a quick in hand inspection, so we decide to continue in hopes that the tone at the date can be minimized. when that starts to happen the coin has already been damaged. we can argue about mirrors, flowlines and luster till the cows come home but they are all essentially the same thing.
JMHO of course.
Having served two tours and being a member on the Nuclear/Biological/Chemical teams in the U.S. Army, let me just add: " Don your masks, children ! "
On a side note : Happy Mother's Day.
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I wonder what 2 minutes intervals of immersion would show. And before and after on an ED coin would be educational.
You will find it very difficult finding a toning agent which will make much of a difference when subjected to being dipped soon after.
It takes time, heat (even if "room" temperature"), ambient humidity and ventilation. To greater and lesser extents. Other idiosyncratic environmental factors may also operating..
But easy enough to try
BUT
I disagree with the following statement if you are referring to early copper or silver coins.
"The desire for tarnish is, effectively, searching for coins with an altered surface."
In fact I believe the opposite is true because the vast majority of these early coins were stored in an environment that caused them to naturally tone/tarnish over time.
They were not stored in a sealed environment that prevented toning.
Therefore the desire for early copper and silver non-toned/non-tarnished coins is effectively searching for coins with altered surfaces.
This is because one must intentionally alter the current natural state of the coin by removing the toning/tarnish.
If this can be done without significantly effecting the original luster and look of the coin then some people believe that the coin now looks more like it did when minted.
Of course this means that the changes that occurred over more than a hundred years caused by the coins environment have been removed using chemicals.
I've seen so many early coins that have been damaged by improper and repeated dipping. As this trend continues early naturally toned coins with their original skin continue to increase in rarity.
When that rainy day comes and you try this again, it would be interesting to choose a coin that has no noticeable toning streak that would lighten over time. I would bet that you could run a "guess the photo order" experiment and ask folks which picture was at the beginning of the experiment, and which was at the end after all the dips. Without the OP putting the photos in order, can folks really tell before and after (without seeing what their biases want them to see in the before and after photos)?
<< <i>Was it dipped before you dipped it? That seems key.
Eric >>
I think this is a fairly silly question because if it HAD been dipped, throw another 10 seconds on the pile.
The name is LEE!
<< <i>
<< <i>Was it dipped before you dipped it? That seems key.
Eric >>
I think this is a fairly silly question because if it HAD been dipped, throw another 10 seconds on the pile. >>
No, I respectfully disagree, the original skin and true original surfaces count for something (if it was there to start aka virgin coin). I submit results were skewed because of this. A "BU roll off eBay" likely has been dipped, NO? What did Andy say (I think it was Andy)- "once its its gone..." YMMV. We are splinting hairs some may not see . Read Keets reponse.
Have a great Sunday
Eric