Recaps history of publisher use of silver and non-silver microfilms for library acquisitions. Reviews characteristics of silver halide, diazo and vesicular films. The author used to support library acquisition of silver film over other types as being more permanent. However, the silver halide film can be termed permanent only if it is properly processed and maintained. Now the author points to the inferior performance of silver film when wet; stored under high humidity; or exposed to paint fumes, acid in film containers and rubber bands, ozone, and oil and other substances from the hands of users. There are second opinions by seven other people from the microfilms world.