Roll format:







The documents are microfilmed on to a roll of microfilm (typically 100' long). Indexing is either alphanumeric or by date.
Retrieval is achieved by winding the film through a reader until the required documents are found.
Most economical format
Slowest retrieval times (approx 2 minute)
All documents need to be sorted prior to microfilming
Hard to update (except when indexed by date)
 
 
Microfiche format:
The microfilm images are arranged on a flat form either as one large image or a grid of smaller images. A typical format is 6"x4" with 60 micro-images of A4 pages.
Indexing is achieved using an eye legible title at the top of the form. The microfiche / jackets are stored like a card index system for reference.








Retrieval is achieved by extracting the relevant microfiche according to the index information, and loading it into a reader.
 
Fastest retrieval times (approx 15 secs)
No need for full sorting of documents (each file is stored separately)
Easy to update
There are also different microfilm sizes to cope with various sizes of original documents.