Format Identification Guide
The following resources are helpful for not only identifying analog audiovisual formats, but also determining a ballpark date for undated media.
Film Formats
Film Formats
Little Film. Has visual aids and dates for small-gauge film (8-16mm).
The Film Preservation Guide's Edge code chart. Film can be dated by looking for the edge codes at the edge of the film, given that they correspond to the film's date of manufacture.
Video Formats
Video Formats
Texas Commission for the Arts Video Identification and Assessment Guide. Includes videotape formats introduced between 1956 and 1999.
Video Preservation Website, Video Format Identification Guide. Includes videotape formats introduced between 1956 and 1995. Less complete, but is a handier, web-based document.