Home Movies (1943)

HOME MOVIES FOR AUCUST • Fig. 3 — Among the many opportunities which the Iriscope system of color reproduction will open up for the movie amateur, is the possibility of making color movies of action scenes, such as this, at night, with all the detail now obtained with high-speed black and white film. that every black and white photographic film thus contains potentials in the emulsion which, in effect, register the original colors of a scene or object photographed. Oddly enough, this result is more pronounced when the picture is photographed with a cheap lens, uncorrected for color. He further explained that the conically converging light rays form minute channels in the sensitive film emulsion during the exposure. The channels become microscopic crystal formations, the axis of each crystal being parallel to position of the light ray that formed it. After the film is developed or processed and then projected, the light from the projector follows the same paths back through the crystal patterns in the emulsion which were formed when the exposure was made, as illustrated in the diagram in Fig 4 The Iriscope, fitted to the projector lens, is designed to catch these light rays and convert them to their respective colors as they pass on toward the screen. The red filter, which is the outside band in the disc, catches those rays coming from areas of the film which registered the red colors when the film was exposed. The green filter, which is the next color band in the Iriscope, catches the green color rays in a similar manner, and the blue filter area of the disc, the blue rays. Red, green and blue are not the only colors registered in the emulsion and reproduced by the Iriscope. Combinations of all three reg ister and reproduce in a similar manner. Although any black and white film may be used in combination with the Iriscope to produce color pictures, panchromatic film is the best because it is sensitive to all colors. Mr. Birch-Field has demonstrated that old black and white films, some as much as 20 years old, can be projected in color through use of the Iriscope, pointing to the fact that color, once registered in the film emulsion, never diminishes nor changes with age. This being true, it is not improbable that, with perfection of the Iriscope, many important motion pictures will be re-issued and screened in natural color, thanks to Mr. BirchField's explorations in the field of optics. His recent developments have naturally aroused widespread interest among photographic engineers and hobbyists alike and have even brought to light one or two other experimenters who have endeavored to create color in projected pictures by means based on similar principles. One of these is George R. Clough of S3 PROJECTOR I I I I I LAMP I I I I I HOUSE RED FILTER GREEN FILTER \ CROSS SECT/ON OF FILM EM VIS ION IRISCOPE FILTER V/5C Galveston, Tex., one of the nation's most rabid cine fans. Clough obtained several of the Iriscope filters and reports his experiments with them have produced results comparable to those claimed by Mr. Birch-Field. Mr. Clough has conducted experiments both with movie film and 35mm. black and white transparencies; and while, thus far, he has been unable to get the same results on movies as did Mr. Birch-Field, his experiments using 35mm, slides have produced good results especially where the original colors were deeply toned as in the flag, etc. Mr. Clough has carefully explored the color results to be obtained with various types of lenses. "The Color is obtained by what is known as chromatic aberration or non-color correction of the lens system in both the camera and projector," said Mr. Clough, "And from my personal experiments, I find that a good lens, such as used on the best movie and 35mm. slide cameras, will not produce satisfactory results in Mr. Birch-Field's process, which is exactly what he claims." Mr. Clough's experiments revealed that a non-corrected lens on both camera and projector will produce quite good color if pan film is used, and fairly good color on the so-called colorblind films at times. On some of his tests with the color-blind film, he was • Continued on Page 264 • Fig. 4 — Diagram showing how light rays of the various colors registered in the film, follow the same paths back through the crystal patterns of the emulsion in conical refraction during projection of film. The Iriscope is adjusted to receive the bent color rays at the proper point so that they pick up their respective colors in the filter and transport vhem to the screen to form the natural color image. 245