What's the difference between half-hard and dead-soft silverpoint?
Silver and Sterling silver* wire are made up of large crystals. As the wire is worked or formed, it hardens. This hardening effect breaks the crystals down into smaller crystals and the wire becomes stiffer and stiffer as the crystals become smaller and smaller. If worked too much, the wire will break. Dead soft wire is very malleable, which makes it easy to work with when bending and wrapping it. Half hard wire, on the other hand, has been tempered to provide some stiffness to it and is less likely to break when manipulating it.
The difference between the type of tempering for most artists is probably negligible. But we have observed slight differences in the handling and resulting silver deposit between the two types. Most artists begin with dead-soft silver or sterling silver and then after developing some experience with silver, begin experimenting with other metals.
The difference in lines produced by dead soft and half hard silverpoints are subtle. These terms describe how the metal has been heat treated (or not) to be malleable, yet maintain its shape under stress during manipulation (which is important when metal forming, such as in jewelry making). The term is not synonymous with the terms used for graphite leads and charcoal pencils.
Half hard silverpoints tend to make lighter lines that have less surface luster when applied to traditional silverpoint grounds and acrylic dispersion silverpoint primers, whereas dead soft silverpoints lay down darker lines that exhibit greater luster.
* Sterling silver is 92.5% silver and 7.5% copper. The copper component in sterling silver causes it to tarnish more readily than fine silver.