Motography (Jan-Jun 1914)

206 MOTOGRAPHY Vol. XI, No. 6. effect is nearly the same as that obtained by simultaneous projection. This is based upon the same fundamental principle as that of the motion picture; i. e., persistence of vision. If a green image is rapidly succeeded by a red image, the eye still retains the impression of the green image at the time that the red image appears on the screen, thus obtaining a combined impression of the two colors. If certain portions of both the red and green images occupy the same place on the screen, the effect is exactly the same as that obtained by overlapping in simultaneous projection. This method requires two and onethird times the speed used either with the black and white pictures or with simultaneous projection. pathe's stencil coloring method. The method adopted by Pathe Freres, Paris, is an example of experience and ingenuity in coloring motion picture films. The method is very nearly automatic, and that part of the process requiring hand labor can easily be performed by comparatively cheap labor. COMPOSITION OF SIGHT. In order to fully understand the theory of colored pictures it should be noted that the sunlight (white light) is composed of seven distinct colors — violet, indigo, blue, green, yellow, orange and red. Together, these colors can be resolved into the white light from which they were separated. These seven colors are known as the "colors of the spectrum," or more commonly as the "colors of the rainbow," since they appear distinctly in that phenomena. Color, as we know it, is therefore the result of breaking up a beam of white light in such a way that one or more of the primary colors (any number less than seven) are thrown out of the main beam and transmitted to the eye. In general there are three ways of breaking up the white light beam; by reflection, refraction, and by transmission, all three of the methods being practised in nature, and at least two of them in motion picture photography. SEPARATION BY REFLECTION. When looking at an object upon which a beam of white light is playing, a portion of the light is absorbed by the surface, and the balance is reflected to the eye. The nature of the reflected light depends upon the character of the surface, some substances absorb a particular part of the spectrum and reflect the rest, causing of course, an impression of color. The colors seen by the eye are the colors reflected from the surface. If, for example, an object appears red, we know that all of the spectrum with the exception of the red has been absorbed. Should two or more colors be reflected, the result will be an intermediate shade caused by the combination of the reflected colors. SEPARATION BY REFRACTION. When a beam of white light strikes a transparent body at an angle with its surface, the beam is broken up into its seven primary colors, forming a band of colors called the "spectrum." In nature the spectrum is seen in the rainbow, the light in this case being broken up by sun rays striking the surfaces of the raindrops from which the various colors are refracted to the eye. In practice, the spectrum is usually obtained by means of a triangular glass prism on which a slanting ray of white light is allowed to fall. Color separation by the prism or raindrop is caused by the difference in velocity or wave length of the different colored rays, the higher velocity rays being thrown at one end of the spectrum band, and the lower velocity rays at the other. Since the two velocity extremes are found in the violet and red rays, it is evident that they will be found at opposite ends of the spectrum, with the remaining seven colors arranged in the order of their velocities. In color photography, the method of refraction has been but little used up to the present time, but since it is a simple means of separating and recording every possible color contained in white light, it will undoubtedly conic into use in the future. COLOR SEPARATION BY TRANSMISSION. When light is passed through transparent bodies, such as sheets of glass, it is seldom that the transmitted light (the light passed through the sheet) is of the same color as the original beam. Different chemical compositions transmit varying proportions of the primary colors, the glasses reflecting some of the rays and transmitting others. By varying the composition cf the glass it is possible to stop the transmission of any desired ray or rays and to reflect the balance. This explains the difference in color obtained by viewing a glass or fluid by reflected light, and then by holding the glass between the eyes and light and obtaining a view of the transmitted beam. Often a glass will appear greenish blue by a reflected beam, and prove a ruby red by transmitted light. There are many fluids that exhibit the properties of the glass just mentioned, a striking case being that of a saturated solution of sulphate of quinine. The film to be colored is mounted between two reels in a chamber, the top of which is part of the working table and contains a ground-glass window on to which is projected, by the light of a Nernst lamp, an enlarged image of the picture being dealt with at that moment. The operator decides which portions of this picture are to be dyed, say red, and then, round these portions, she guides a stylus carried by a pantograph link work which is so proportioned that the motion of the tracing stylus is reduced in exactly the same ratio as the film picture is magnified on the ground-glass screen. The reproducing point of the pantograph consists of a fine needle which is vibrated up and down by the ingenious mechanism roughly sketched in Fig. 59. The winged plate 5\S\ carried by a vertical spindle, is rotated by the attraction of MM when the latter are excited. Hitherto, the tiny connecting rod C (which has ball joints at each end), has been in an oblique position; but the rotation of 5\S" forces C, to approach a vertical position thus thrusting down the block B, and hence, through a sleeve coupling, the stencil cutting-needle N. The deflection of 5" automatically breaks the field circuit of MM and, the moving parts being spring controlled, there is secured a rapid vibration of N, which is maintained so long as a master contact is closed by the tracing style being held down against the glass-tracing screen. (To be continued.) American Makes "New Departure Pres. Samuel S. Hutchinson, of the American Film Mfg. Co., announces that his company is preparing to put out a number of big features. These productions will excell anything heretofore put out by the American and the success of the "Flying A" as well as the "Beauty" subjects assure some big American releases for the coming year. It is not intended to maintain a permanent company for these special features. Players of prominence will be gathered from the dramatic profession, but each company will be disbanded after the completion of a production.