Artificial Antique Tone - Ammonium Polysulphide!

[Coinery]

I've been meaning to share this for some time, but kept forgetting to photograph it! This was a gleaming BU-bright, coin, which became part of a series of my own experiments into what could be achieved with various different chemical processes!

As with dipping, this was something I carried out as part of my own 'practical' studies into what could be achieved by the unscrupulous, and what I could look out for in the future! This particular coin has bounced around in my wallet for about 6 months now, so is looking rather bag-marked!

It is one of the better results, but I noted others which, whilst they looked convincing, they never quite made the grade, so to speak! I have seen coins on the 'bay which have looked so close to some of my own 'nearlies' that I have left them alone.

Anyway, just thought I'd show you, if only to add another dimension to dipping and toning!

Incidentally, the cooked yolks of boiled eggs was another good result, though a tad whiffy!

[Peckris]

BU? There are definite signs of wear there, or did you add them too?

[Coinery]

BU? There are definite signs of wear there, or did you add them too?

Sorry Peck, I meant BU-Bright in colour, not grade!

[Peckris]

BU? There are definite signs of wear there, or did you add them too?

Sorry Peck, I meant BU-Bright in colour, not grade!

Ah, got you

[TomGoodheart]

Interesting. Any idea what it does to silver? And where to you get Ammonium polysulphide anyway?

As an aside, I always wondered about B&W photo developing chemicals. After all, photographic paper was coated with a light-sensitive silver halide I seem to remember ... silver salts, well you get the idea. My chemistry is very rusty I'm afraid!

[DaveG38]

Interesting. Any idea what it does to silver? And where to you get Ammonium polysulphide anyway?

As an aside, I always wondered about B&W photo developing chemicals. After all, photographic paper was coated with a light-sensitive silver halide I seem to remember ... silver salts, well you get the idea. My chemistry is very rusty I'm afraid!

Basically, some sulpher compounds react with the surface on a copper or bronze coin to produce copper sulphide, which is black. In a thin enough layer, with the underlying copper showing through it will give a nice deep tone. My bet would be that those early copper coins that show a really black tone have had long term exposure to sulpher in the atmosphere, caused by burning coal in power stations etc.

[Coinery]

Any idea what it does to silver? And where to you get Ammonium polysulphide anyway?

Its best effect is on silver, it's used predominantly by the jewellery industry to 'age' silver for artistic effect!

I learnt a lot from playing around with the various combinations, also using toothpaste for highlighting! Hammered coins can be totally blackened and then highlighted to look similar in effect to the reverse of this coin (which is 100% natural toning in this example, I hasten to add, though I'd say it's been 'artistically' cleaned/highlighted in the past - very pretty, though)

I must state clearly here that I have only ever experimented with artificial toning to better my own understanding of what makes for a tampered, or recently toned coin!

When done well, it's very difficult to tell! However, success isn't always guaranteed, the variables are immense and, statistically speaking, I'd say the imperfect result weigh at 75%, so of no use to the numismatist! Good for spotting the crook's attempts though, which are far and few between it's fair to say!

Edited December 30, 2013 by Coinery

[scottishmoney]

I'd like to see before and after pics as well.

[Coinery]

I'd like to see before and after pics as well.

Sadly I don't have any, and certainly not of the E1 shilling, as that's a genuine tone!

I'd be happy to revive this thread next year sometime with some before and after images, if that would be of interest?