Capped Bust contrast black field “white” stars and devices, HOW & WHY?

Aspie_Rocco

I have noticed the stark contrast found on a lot of capped bust coins and I am curious how this design has such a “black & white” cameo appearance so often.

Is it just undisturbed tarnish on the low points?

Is this the result of using an Eraser on stars and high points? A numismatic No-No

Also can someone show and/or explain what an eraser was used for in the past (With coins)
For example

Eagleguy

Years of friction/rub from commerce?

Nysoto

A combination of two types of friction. The first is circulation, the high points receive the most friction in pockets, merchant shuffling, etc. For those who remember silver coins in circulation, they were lighter in color on the high points. The second type of friction is cabinet friction - drawers, collector handling, slides, envelopes, dealers shuffling through shows - "cabinet friction" is considerable and shows on the high points, the tarnish remains in the low areas.

DIMEMAN

@Eagleguy said:
Years of friction/rub from commerce?

yep,

NSP

I don’t think there’s any way to know for certain, but I have a couple of ideas about how the “circulated cameo” appearance may occur.

One probable way this could occur is if the coin was put aside for years and allowed to develop a dark patina. Things like coal-fired factories would’ve discharged a lot of chemicals (like hydrogen sulfide) into the air that would’ve promoted toning. If the coins were ever spent after they toned, the high points (stars and devices) would wear more than the low points (fields) would. This would result in the “circulated cameo” appearance.

Another way that this could happen is that when the coins commonly circulated, the patina would more readily form in protected areas while the high points would remain worn and bright. Things like hydrogen sulfide would react with the silver on any part of the coin, but in the unprotected areas the corrosion products would be worn away.

JasonGaming

I agree with the others. A dark patina developed and then the coin circulated, particularly on the high points. Fields stay dark and the higher points turn lighter. This causes circulation cameo.

Smudge

When that coin was made homes were heated with wood. Then coal. Tarnished silver fast I guess.

ricko

That is tarnish and wear from commerce and also storage...no way to determine how much of each contributed to the appearance. Cheers, RickO

keets

terminal tone overall, removed from the high points of the design by years of friction. here at the forum that is known by the term CircCam.