Ultra Cameo is a designation that applies only to proof coins. It is the measure of the contrast between the frosted devices (raised portions of the design) and the mirrored fields (all the flat areas of the coin). On a Modern coin, you should expect for it to be Ultra Cameo. When you get to older proofs, it is often times an exception, not a rule, that a coin be Ultra Cameo, or even Cameo. Cameo is a designation for a coin that has a certain amount of contrast, but not enough to be called Ultra Cameo. Unfortunately, there is no hard and fast rule about measuring if a coin is Ultra Cameo, Cameo, or not at all. This is something that can only be gained through the experience of looking at and studying many coins. As with all of numismatics, look at as many coins as you can. It is the best way to learn about them.

Here is an example of a proof coin for you to see. All of the white areas of the coin are frosted on the areas referred to as the devices. The black areas of the coin are the mirrored fields.