A few conclusions stood out from the research. One was that films were great at giving overviews of a situation or an operation. However, they were less successful at getting over the details. Some general features of film (and, later, television) stand out. One is that a film goes at its own pace. Another is that no specific responses or activities are required from the viewer. A third is that the audience is varied, sometimes hugely varied. This gives clues to ways of improving instructional films.