Neon Toning: Strict Defintion? Causes? Examples?

WingedLiberty1957 · January 14, 2013 2:34PM

With all the excitement and discussion over the past few days of the neon-toned Capped Bust Half that was bought off Heritage by one of our esteemed members. It got me thinking about neon toning.

Here is a photo of said coin that was posted by member Justacommeman:

I believe that the one series that has more neon toned examples than any other is the Morgan Silver Dollar series. And from what I have seen, PCGS and/or CAC blessed neon toning is rare in other series.

I then picked though my archive of over 200 colorfully toned coins to see how many neon toners I had and could only find two that I thought had neon or neon-like toning.

My obvious neon toner:

A possible neon toner?? Although this doesn't seem so obviously neon.

A couple of questions:

1. Is there a strict definition of how someone determines if a coin has neon toning? That is, are there certain quantifiable qualities or colors that must be present for the term "neon" to be applied?

2. Does anyone have any knowledge or insight on how neon toning forms, and why it is so rare?

I would also like to see if anyone else has any coins that exhibit neon or neon-like toning. Feel free to post.

coinsarefun · January 14, 2013 3:48PM

I'm not really sure I would classify this as neon but it sure has nice bright lime green with a hint of pastels in it>

This one was described as iridescent and it really is and pretty close to neon and as I understand not all that common for ancients.

And lastly I would describe this as neon as you have seen in hand I think you would agree

Justacommeman · January 14, 2013 4:13PM

<<With all the excitement and discussion over the past few days of the neon-toned Capped Bust Half that was bought off Heritage by one of our estranged members>>

Here, fixed it for you. AnkurJ was given a one way ticket from the county seat to Palookaville

(using some get out of jail emotions)

MJ

coinsarefun · January 14, 2013 4:14PM

Another side note after researching the words neon and iridescent toning I think iridescent might
be more appropriate as I have found several definitions for this.

One site describes it as:

Iridescent - Probably the most desirable form of toning on a silver or nickel coin. Iridescent toning covers virtually all of the coin's surface, while still permitting all of the coin's natural lustre to shine through with its full intensity. Some numismatists feel that in order for toning to be called iridescent it must have all the colors of the rainbow, or at the very least, most of them.

A registry set is described as Gobrecht's Golden/Iridescent Raisinet Collection

And another registry collection named The Silver Gypsy Collection

Kaelasdad · January 14, 2013 4:23PM

A few of my favorites

WingedLiberty1957 · January 14, 2013 9:45PM

Nice examples everyone!

I think you might be onto something CAF about the rainbow ROYGBIV quality being something that really makes any neon quality really pop ,,, or certainly at least Reds, Yellows, Greens, and Blues. One thing that strikes me (visually) about the CBH are the blues and greens, they almost seem to glow as if their was some sort of internal light source. Or they were some sort of ghostly apparition.

I think the fact that my Morgan example contains no blue color, it makes it seem less neon, even though it does seem to glow and has smooth transitions.

Another very appealing quality (from a color perspective are the incredibly smooth transitions between colors, there is just no choppiness at all. I think it might be the smoothness of the color transitions that makes this coin especially visually appealing -- and makes the color seem more light -- or what you would see as light source colors blend together in a true rainbow spectrum.

One last thing that I think might make the CBH especially interesting visually is it displays a SINGLE classic rainbow in the classic order ROY G BIV (occurring in a somewhat circular (or at least concentric ring) pattern. This is a quality that I think is really rare, as I don't ever recall seeing it on any other coin (perhaps someone can find another and post it).

With the other "neon-like" coins posted, the colors seem to repeat and are a bit mixed up and don't follow the classic ROYGBIV progression.
Perhaps they are following the Sunnywood Toned Coin Color Progression instead?

BAJJERFAN · January 15, 2013 12:12AM

Here is one. TeleTrade original pic.

renomedphys · January 15, 2013 2:22AM

Had the sunnywood scale applied to this one before:

Here's what he said:

<< <i>Hi Matt,

Sorry, I just didn't have the time to give you a proper answer. It's a little complicated. Basically, there is a difference between copper and "white metals" like silver. White metals are essentially colorless in appearance because they reflect all wavelengths of light equally, and absorb little. Copper has a natural "orange" color because it actually absorbs certain wavelengths of incident light, primarily in the blue-to-green range.

The thin film interference phenomenon that produces the colors in my color chart depends on the fact that as light hits a toned coin, some of it bounces off the upper surface of the toning layer, while the rest penetrates the toning layer and bounces off the underlying metal substrate (i.e. the surface of the coin). Because the the light penetrating the toning and reflecting off the substrate travels a slightly longer path, the two reflected beams are out of phase, and you get intereference (which can be destructive or constructive, i.e. cancelling or reinforcing various wavelengths).

With copper, the second beam, i.e. the light that penetrates the toning layer and reflects off the underlying surface, is further subject to the fact that the underlying copper surface may absorb some of the blue-green wavelengths. Therefore, the reflected light may be less than full spectrum. This changes the color sequence somewhat as versus what happens on a silver coin.

A further complication is that certain oxides and sulfides of copper exhibit blue or green pigments as well (meaning that they absorb red light).

So some colorfully toned copper coins can be mapped using my chart, when these two phenomena are less prevalent, but the chart doesn't always work as perfectly for copper as it does for silver, for the reasons mentioned.

Doug / Sunnywood >>

bestclser1 · January 15, 2013 2:37AM

Neon Toning: Strict Defintion? Causes? Examples?

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