Full hard. Half hard. Dead soft. This is jewelry jargon? It sure is, and it confuses a lot of people. Lets try to clear it up!
Fully tempered metal, very stiff and, well, hard! It's very difficult to manipulate, especially in heavier gauge wires.
This is stiffer than dead soft wire, but not yet full hard. Makes beautiful ear wires that maintain their shape.
Very pliable, unworked metal (wire) and my personal preference for most jewelry work.
The more you "cold work" metal, the harder and, ultimately, the more brittle it becomes. Theres a fine line between "hard" and "broken!"
Manipulating the metal by bending, hammering, coiling, tumbling, even slapping with a rubber spatula (for real...don't laugh) will harden metal to different degrees. This is called "work-hardening" and is actually a physical change to the molecular structure of the metal.
Sterling silver may be hardened by heating to 600 degrees F for 30-50 minutes to 3/4 hard.
Other wire-related topics: