dark to bright pictures shock the eye. Second, sudden shifts from a picture in a "cool" tint to another in a "warm" tint, and vice versa, over-work the eye. Third, a series of quick close-ups or other pictures in which the frame is filled with the subject demands too much eye-movement.
In the case of the close-up, or any large picture where the points of interest are scattered all over the field of vision, the eyes, as we have said, become strained by too much rolling, a muscular effort which is necessary even though the separate points of interest may themselves be fixed, as fixed as the four corners of the screen itself.
But when the points of interest are moving things, as they generally are in the movies, new causes of strain often arise. Sometimes the object we are trying to look at moves so fast that we can hardly follow it. Quick movement is generally desired by the directors because they think that briskness, or "pep," makes the dramatic action more intense. Consequently people in the movies walk, march, dance, fight, and carry on with terrific speed until our eyes become tired in the attempt to observe all that is happening. The cure for such pictorial hysterics is simple moderation, the elimination of jerky movements wherever possible, and the choice of movements so easy to follow that the eye may perceive them with the least muscular effort.
We do not say that you who worship speed shall not have your express trains, your racing cars, your airplanes, your cow-ponies, and your Arabian steeds. You may have them all, because they can be so photographed that an actual run of two or three miles may
