Brown Ike Discoloration

Earle42, your understanding is correct, Cameo refers the contast of the slightly roughed surfaces of the devices comparted to the mirror smooth surfaces of the fields. The term comes for the jewelry field where a cameo was a white engraved bust on stone or shell on a black stone background. In the case of a proof coin the devices have a slightly roughened surface created by the unpolished recesses in the die. When light hits a proof coin at an oblique angle the light that hits the fields is also reflected off at an oblique angle and not into the viewers eyes. this gives the fields a "black" look. But the light hitting the devices is scattered in all directions including into the viewers eyes making the devices much brighter or "white", against the "black" surfaces of the field. The finer and sharper the roughness is on the devices the greater the scattering and the "whiter" the devices, and the greater the cameo contrast.

The milky contamination of the fields of a brown Ike (and it does come from outgassing of the plastic holder) reduces the visible contrast because the film reflect light to the eyes as well.

Why do so many of the brown ikes show this film? I think it is because they are so common that they were hard to sell and back in the 1970's a great many of these coins traveled from show to show to show in the unairconditioned trunks of dealers cars (no minivans back then and most dealers just drove sedans and carried their coins in the trunk.) So those brown Ikes got baked time after time at 140 degree temperatures traveling from show to show. The high heat cause the plastic to break down and outgas with the fumes condensing on the coins.

It explains why all of mine have the problem. They were all cracked from OGP holders in the early nineties.

The ~20 years in those plastic did not do them any favours, but I love them just the way they are.

Conder = thanks for the verification. I always thought the word cameo was a jewelry take-off.

Now I know I am going to break my one Brown Ike (still in the case) out.

I just cracked open a 1979 Proof set. All the coins are nice and clean except the SBA which has the same haze (frosting, if you will) I've seen on Ikes. Could this be a dollar thing?