1883 N/C, AT or NT?

That's true in general, but it gets a little complicated for toning. Like a rainbow, toning separates the colors of the spectrum -- and if your spectrum is uneven, toning will look different. LED lights tend to have a big spike in blue and a broad hump from green through red. CFLs tend to have a broad spectrum with spikes at various colors.

I don't have a well-controlled setup to demonstrate this, but now you've got me thinking about how it could be done.

 

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I use LED lights and toning usually turns out fairly similar to what what non LED photos do. I'm not sure what Phil uses at PCGS, but I'm fairly confident his lighting is something other than LED.

LED


Not LED


LED

Not LED


LED

Not LED


LED

Not LED


LED

Non LED

 

It isn't the result of aging. Something happened to it, and pretty abruptly.

 

I see tantalizing differences in several of these shots, but I don't think they're due solely to spectral differences. I think it would take a fairly sophisticated setup to compare LED, CFL and incandescent directly. I'm picturing setting a bulb of each type behind a two-stage diffusing screen so that bulb shape and radiation pattern don't influence the results.

 

I voted AT. The obverse had me going a little, but the overall look and the darker spot on the reverse prompted me to vote AT.