microform

/ˈmaɪkroʊˌfɔrm/
noun
  1. A process or material for storing documents as very small images, such as microfilm or microfiche, that need a special machine to be read.
    • The researcher used a microform reader to view historical records.
    • Old newspapers are often kept on microform to save space in libraries.
    • Many government documents were transferred to microform before digital scanning became common.