Because audiovisual media are so easily damaged, restoration is an important process in preservation. A restored item is never completely the same as the original one, even though it might look and feel the same or better.
Restoration has its successes and failures. There are defects that can be repaired, and others that can’t (or not so well). Also there are differences in the technology used for restoration: some techniques work better on some defects than others, and some techniques are very specific. Therefore restoration is not a single process, but a complex process that will use many tools to do many things – all with varying degrees of success.
There are many tools that can be used for restoration – and terminology can be confusing. This tutorial gives a roadmap to the general types of restoration tools.