Manual of Photography, 9th Edition

22Life Expectancy of Imaging Media

In this chapter we will consider general aspects of the archival or life expectancy of different imaging media. Previously the term archival was used to describe materials with a long life, which is now taken to mean a minimum of 100 years. The new electronic media have expected lifetimes of less than 100 years and it is now generally agreed that the term archival be substituted by the term life expectancy. All materials degrade over time and differing imaging media are subject to many causes of degradation, many of which are now well understood. Steps may be taken to ensure that their life expectancy is as long as possible. As imaging systems advance and new systems evolve the initial prime criterion is to ...