A film transport mechanism moves film from area to area and then stops it to project an image. During the period while the film is being transported, the lens is shuttered and glass flats on either side of the film are opened. This way, the viewer does not see a blurred montage of images being moved across a screen at a high rate of speed, and there is a much less chance of scratching film. The shutter may be either a mechanical blade which cuts across a beam of light or an electrical circuit which dims a light supply to darken the screen. Dimming is preferred to switching a lamp off or on since it is much less damaging to a filament if it remains continuously energized.