Page:Pictorial beauty on the screen.djvu/56

 *scribe, if the reader will help us by making an experiment. Close one eye and look steadily with the other at an object across the room. Now, without changing your gaze, hold up your finger in line with this object and about a foot away from your eye. The outline of the finger will be indistinct as long as you keep the eye focused on the remote object. Now, still keeping one eye shut, look at your finger until you can see the little ridges on it. The eye has changed its focus, and the remote object is now indistinct. What happens is that the lens within the eye changes its shape, bulging more for near objects and flattening again for distant objects. This work of the eye, called accommodation, is done by certain delicate muscles. A little of it may be stimulating, but too much will make the eyes tired.

Now it is a strange thing that certain colors affect the eyes in the same way as distances. Painters knew this fact for hundreds of years before the scientists were able to explain the reason. They knew that blue seemed farther away than red, and arranged the colors in their paintings accordingly. All artists have learned the trick, even some of our commercial artists, who make advertising posters for street cars. Blue makes the background fall back; red makes a figure stand forward. The reason for this illusion is that when the eye looks at red it adjusts itself exactly as if it were looking at a near object, and thus deceives the brain, so to speak; and when it looks at blue it adjusts itself as if it were looking at a distant object and again deceives the brain. Or, to state the fact more completely, a color from the red end of the color scale (red, orange, yellow, green, blue, indigo, violet) seems