Film strips

The film strip or filmstrip are a audiovisual communications mediaand was a common form of still image instructional multimedia, commonly used by educators in primary and secondary (K-12) schools up until approximately 1990, when it was overtaken by newer and increasingly lower-cost full-motion videocassettes and DVDs. From the 1940s to 1980s, filmstrips provided an easy and inexpensive alternative to 16mm projector educational films, requiring very little storage space and being very quick to rewind for the next use. Filmstrips were also large and durable, and not prone to ever needing splicing.

Technology
A filmstrip is a spooled roll of 35 mm positive film with approximately 30-50 images, arranged in sequential order. Like 16 mm film, a filmstrip was inserted vertically down in front of the projector aperture, rather than horizontally as in a slide projector. Due to this, the frame size is smaller than normal 35 mm film. Two image frames of a filmstrip occupy the same amount of space as a single 35 mm frame, including its guard band, so that a 25 exposure 35mm film can contain 50 filmstrip images. Early celluloid filmstrips had a habit of melting or combusting from the intense and sustained heat of the projection lamp.

Typically, a filmstrip's running time was between 10 and 20 minutes. Depending on how they were narrated or produced, filmstrips (which often came with an Instructor's Guide) were flexible enough to be used in both self-paced learning formats, or in a full classroom. In additional to a standard classroom wall or screen projector, personal film display units were available with a screen size of approximately 8 inches diagonal, for up-close viewing by one or two people.

The instructor would turn on a film projector that would show the first frame (image) of the filmstrip. The instructor then turned on a 33 RPM record or cassette tape containing the audio material for the filmstrip, which included narration. At the appropriate point, a tone would sound, signaling the instructor (or a student volunteer) to turn a knob, advancing to the next frame. Later technical improvements (described below) allowed the projector to advance the film automatically.

Film production
By the latter part of the 1960s, such firms as Warren Schloat Productions, Inc. of Pleasantville, NY; CBS; The New York Times; Scott Education; Coronet; Sunburst Media; and Guidance Associates, Inc. of Mt Kisco, NY were producing titles featuring photographs by famous artists and of notable events with a synchronized audio track. An example of such a title was "Folk Songs in American History", written and produced by Charles Bergwall for Warren Schloat Productions. The music and narration for the filmstrip originally came on a vinyl album. (Note: in 1968 Warren Schloat Productions, Inc. was purchased by Prentice-Hall Publishing and was renamed Prentice-Hall Media. Prentice-Hall Media was sold by Prentice-Hall to Guidance Associates in the mid-1980s.)

In the early 1970s, audio technology advanced and vinyl albums gave way to audio cassettes, and filmstrips moved beyond traditional arts and humanities courses, branching into the sciences and vocational/technical subject areas. This shift was led by firms such as Bergwall Productions, Inc. of Garden City, NY; DCA, Inc. of Warrington, PA; MedCom, Inc. of Garden Grove, CA; National Geographic; and Brittanica. Major universities such as Cal-Poly San Luis Obisbo and University of Ohio also shifted to the use of audio cassettes.

Automatic film advance
During the 1970s, advanced projectors became available, and these projectors would automatically advance the film by means of a 50 Hz subaudible tone recorded on the cassette that would be detected by the projector, and automatically advance the frame. In fact, most cassettes accompanying filmstrips in the 1970s and 1980s would have the audio material on one side with audible tones for older manual projectors, and the same audio on the other side of the cassette, but with subaudible tones instead for automatic projectors. Some select filmstrip releases also had both audible and subaudible tones combined, making the filmstrip and its companion cassette compatible with any filmstrip projector. However, if improperly set up, the narration and film would not be synchronized.

Decline and obsolescence
The 1980s brought the advent of the video cassette recorder (VCR), and advancing technology meant increasingly affordable VCRs. When they became within reach for most school districts' budgets, this marked the beginning of the end of filmstrips. Video instruction combined the ease of the filmstrip with pre-synchronized audio and the dynamic images of television. By the early 1990s, the vast majority of filmstrips producers, who were not equipped to compete with video, closed or sold their businesses. Among the few that made the transition were Bergwall Productions, Inc. of Chadds Ford, PA and Films for the Sciences and Humanities (Princeton, NJ). These two companies thrived as suppliers of video-based instructional materials, and continue to do so today.

The instructive methodology pioneered through the 35 mm filmstrip is still very much alive today, as demonstrated by Internet-based instructional and information products. Audio-visual instruction is a powerful learning tool - regardless of how it is delivered - and will remain so for years to come.