Is this just the photos?

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I understand the difference in the toning aspect. The coins could show some signs of toning but we don't have proof of color to attribute it to. Your examples do show a coin that is expected to have some original toning and a much easier example to associate it with what is being conveyed.
If we use Ron's example which doesn't show a change in color around the peripheral devices. But still shows fields that look interrupted ( not showing luster).And he also states that his example isn't toned.
Then we have only the photos to attribute the change in the fields.
I have seen this on a few nickels of this era "the smooth proof like strike on a business strike coin" I think I will try to replicate it to show what I am seeing.

 

I here ya @GDJMSP Some toning is just so minute that I am not considering it for the over all reason even though I should.

 

I really like the theory of work hardening.

Let's take another look at my 84-P Jefferson.



I use 9 photos to make my animations. Of those 9, this lighting angle shows off the haloing around the devices most strongly. The two arrows show the boundaries of areas of haloing that wrap the letters WE and appear at the edge of the nose and lips.

The photo above showed that these areas both have mirror-like reflectivity. And there is minimal toning - you can see only the faintest hint of orange above and to the left of the rightmost arrow.

As I learned on this forum, the metal has to flow inwards from the rim to fill up the large depression in the die that becomes Jefferson's bust. Metal also has to flow up into the letters. This latter flow happens in close quarters - within the W the metal has to flow into multiple close branches of the letter.

It just makes sense to me that higher stresses are suffered by the metal where these boundaries occur. That effect should be reflected both in the planchet simply due to metal flow, but it also stresses the die and deforms its surface too.

Further, we should go back a step and consider die reproduction. The process of stamping a pattern into the die also affects both the positive and negative dies and they also have high stresses where the metal must flow most radically. So we may also find these patterns becoming engrained in the dies and masters.

As to specifics, we have a halo around the letter edges that could be due to increased metal flow up into the devices. That would cause a different surface structure - perhaps a precursor to what we see as die erosion. In the fields, the flow is more of a straight compression, since the planchet is being made thinner here but is fairly distant from the more lateral flows that fill the devices.

This is all speculation, so let me know if it's hogwash. (And why, preferably!)

 

Duh.

Imagine being a coin. In a slab, mint OGP, or whatever. Not too breezy in there is it?

I'm pretty sure the sulfur molecules will become fairly evenly distributed throughout the volume of air surrounding the coin, exposing every nook and cranny equally to all sulfur molecules trapped inside there.

 

Well, they don't tend to tone too much in a slab. And we're not talking rushing wind, just the natural circulation of air over time.

This is what leads to "elevation chromatics" - a term you'll see used when discussing naturally toned coins. Look back at the Morgan that Lehigh posted. Look at the headband particularly - you see how the band has one set of colors, and the lettering has a different set of colors? That's because of the air flow across the surface of the coin - different "elevations" will have different "chromatics". This is a strong indicator of natural toning (although not foolproof).

 

I don't know how to verify that airflow theory or the work/strain hardening theory is the reason for the toning on the OP's or @Lehigh96 's coin. But I would bet on the work/strain hardening theory. As an engineer it makes more sense than some airflow nonsense

But like I said, I can't prove it.

 

The airflow theory isn't nonsense, and it is widely accepted as the reason for elevation chromatics, so it stands to reason that other protected (recessed areas) of the coin would experience the same thing.

The work hardening theory is for pull away toning which doesn't extend nearly as far as the untoned areas on these coins.

 

It's not nonsense. You may have seen this with coin albums. The coins close to the edge of the page may tone more than the coins at the center of the page.

 

Using Ron's photo.

I would call it a die stage. This looks like a loss of luster in the fields from die use. Not just an elevation change in the toning.

So I think we can attribute those parallel halos around the devices towards a possible polish of the die and toning. I had a hard time just seeing them as elevation chromatics. And was trying to interpret the die stage and actual surfaces of the die, not thinking about the toning aspect on such a white coin.
Thanks ya'll
Great photos Ron. And a neat coin thanks for sharing.

 

Always glad to share and happy when someone takes an interest!