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<p>[QUOTE=&quot;desertgem, post: 674686, member: 15199&quot;]Seriously, I have read this statement often, even in PCGS detection book, and I think it is more confusing than helpful. This is how I interpret the phenomena. We are all familiar with the ^^^^^^^^^^^&nbsp; surface of the coin that is still near the UNC grade, and a minimum amount of dipping. This is what produces the cartwheel effect and most of the luster ( some is just metallic reflection).</p><p><br /></p><p>What I think they are implying&nbsp; is that using a liquid toning solution, only affects the tops of the&nbsp; ^^^^, as it will only be there for a short time, and the cohesion of water will not normally wet enough to get to the bottom of the microscopic ^^^. Whereas long term ( natural) toning from sulfur compounds out gassing from a&nbsp; paper album, tones the whole sides of the ^^^^ and thus moves as the cartwheel moves.</p><p><br /></p><p>However, I think that the type of AT that troubles all the most is not liquid based, but gas applied as concentrated sulfurous gases like H2S as White experimented with in his book(and on PCGS and NCG slabs to show toning inside a slab). By using laminar flow setups, the gas can be applied and evacuated as needed to replicate the toning from the gas of the cardboard book. Thus it should pass the test quoted above with little problem.&nbsp; All theoretical and IMO. I think the statement can be applied to AT with liquids, but not with gas.</p><p><br /></p><p>Jim[/QUOTE]</p><p><br /></p>

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