Page:Pictorial beauty on the screen.djvu/50

 often seen photoplays that did hurt the eyes. Some of the reasons for this will be given in the following paragraphs.

A familiar operation of the physical eye is the contraction and dilation of the pupil. We know from childhood that the pupil grows large when the light is weak, and small when the light is strong. We also know that the eye cannot make this adjustment instantly. If a strong light is suddenly flashed on us, for example, when we lie awake in a dark room it dazzles us, because our pupils are adjusted for darkness; it even hurts so much that we defend ourselves by closing the eyelids.

In exactly the same way our eyes are shocked by the movies when a dazzling white light is flashed on the screen where a somewhat darkened scene has just vanished. The pupil is caught unawares, is not instantly able to protect the eye, and, besides, must use up a certain amount of energy in adapting itself to the new condition. Such a shock once or twice during the evening might easily be forgiven and forgotten, might, in fact, be hardly felt at the time; but fifty such shocks in a five-reel photoplay would certainly weary the eye, and a play of that sort could hardly be called beautiful.

The fault which we have just named lies in the joining of scenes. But it is not, as a rule, necessary to connect scenes or sections of a film so that there is a jump from the darkest dark to the whitest white, or vice versa. This can be avoided, of course, by the device of "fading out" one scene and "fading in" the next, which gives the eye time to adapt itself, or by "fading down" or "up" just far enough to match the