had been microfilming

• past perfect progressive

  past perfect progressive

  Used to describe an action that was ongoing continuously in the past up until another past event interrupted it.

  of microfilm.
  microfilm

  noun

  a film bearing a miniature photographic copy of printed or other graphic matter, usually of a document, newspaper or book pages, etc., made for a library, archive, or the like.

Related Words

• image
• likeness
• photo
• picture
• portrait
• print
• snapshot