What’s the difference between “UCAM” and “DCAM”?

Both DCAM and UCAM designate coins with strong frosted devices against clear, mirrored fields, and the terms can be used interchangeably. UCAM (“Ultra Cameo”) is used by the Numismatic Guaranty Corporation (NGC), and DCAM (“Deep Cameo”) is used by the Professional Coin Grading Service (PCGS).