Home Movies (1943)

HOME MOVIES FOR AUCUST • Fig. I — A simple three-color filter disc is the basis of the Iriscope by which projection of black and white motion picture film reaches the screen in natural color. spectrum — red, green, and blue — in concentric circles. The disc is illustrated in Fig. i on this page. Optical engineers agree that wave ltngth variation of color has variable focal points which is the key to Mr. Birch-Field's experiments. Even in the human eye. red and its variations focus in front of the retina, and blue and its variations focus in back, while yellow and those colors in the middle of the spectrum are normally on the retinal plane. How color becomes registered in the structure of the film emulsion is an interesting story, especially to those who have projected black and white films countless times without observing any trace of color. According to Mr. BirchField, when light is focused on a film MOVIES IN COLOR FROM BLACK-AND-WHITE FILM! Current research points to lowcost post-war color movies for all! By FREDER °f the post-war hopes of the average movie amateur is that color movies will become less expensive to make. The wish may be nearer realization than is generally believed. Actually, post-war color movies may not require special color film at all but instead, the old reliable black and white film with which amateur movies made its debut. It seems that color is actually recorded in the emulsion of any black and white film especially when the film is exposed in a camera fitted with a lens uncorrected for color. To bring this color to the screen, all that is necessary is a special color filter fitted to the projector lens which collects the various color rays projected from the film and directs them in their proper order to the screen. All this sounds so simple that one reasonably asks why film manufacturers and the makers of projectors did not make the discovery long ago. But I C FOSTER the fact is the principle was discovered 100 years ago. It has been "re-discovered" and developed during recent years by Charles Arthur Birch-Field of New York City, retired advertising man, artist and scientist. To Mr. Birch-Field is credited the development of the Iriscope which is the special tri-colored filter that is fitted to the projector lens and which converts the light rays passing through the black and white film to their original natural colors. The Iriscope is a simple transparent disc dyed with three colors of the • Fig. 2 — Diagram showing manner in which a camera lens, uncorrected for color, focuses the primary elements of light on a film emulsion. Cross-section of film emulsion is purposely exaggerated to illustrate how the various colors register at different depths. by a lens, the various colors do not come to actual sharp focus at exactly the same distance from the lens. (See Fig. 2). It seems that violet and blue light are more sharply bent in their path after passing through the camera lens than is red, and therefore these colors focus nearer to the lens. With the blues focusing sharply in the front layer of the film, the reds will be in focus at a point much farther back as shown in Fig. 2. This result is more generally known as chromatic abberation. It was Mr. Birch-Field's discovery 244