The motion picture projectionist (Nov 1929-Oct 1930)

January, 1 930 The Motion Picture Projectionist 31 Subtractive Color Cinematography By Professor Rodolfo Nam i as* THE only process of color cinematography which has so far been put into practice is the process whereby the analysis or selection is limited to two colors and synthesis is obtained by superposing two series of monochrome images — one red and the other green. A single film takes the two perfectly coincident images, the red on one side and the green on the other. The images are of normal dimensions and the film is projected by the usual apparatus, the only requisite precaution being to ensure that there be plenty of light, in view of the greater opacity of these color films as compared with the usual ones. Patent Considerations No description of the processes by which such bi-chromatic films are obtained has been published, nor can the process be protected by patent, since the principle of selection, like that on which the synthetic process is based, is public property. The technique to be followed for the production of such films has been reconstituted by the author in these notes, in the light of an examination of several pieces of bi-chromatic film and of a number of experiments. It is clear that, while we may be able to lay down the technical bases of the several operations and more especially to give particulars regarding the production of the two series of monochromes, it is impossible to say anything on the mechanical part of the process, which must undoubtedly present difficulties; these however are not so formidable that they cannot be overcome in laboratories specially devoted to mechanical cinematography. The Negative Film The first question that naturally arises when observing these two-color films relates to the negative film from which they are produced. How was this film obtained? Was it made on one and the same film, by alternating the two images through a green and orange colored screen? In this case it would hardly be possible to obtain the perfect coincidence of the two successive images, especially where a subject in rapid motion was photographed: and yet the writer has been unable to trace by even microscopic examination defects of coincidence in any two-color images. It is true however, that in none of the films observed did the subjects or scenes represented suggest that there had been any rapid movement. Or were two objectives used and superimposed one on the other, thus obtaining simultaneously two images through two selective filters on the same film? In this case, however, it would be requisite to arrange for the slight convergence of the two axes of the objectives or to adopt General Russo's system to remedy the phenomenon of parallax. We should still, however, be faced with the difficulty of having to change a portion of the film corresponding to a double normal image, involving a somewhat vigorous pull on the film. The first system is the simpler and, in the case of staged scenes, it would not appear to be difficult to restrict the movements of the subject to an extent that would obviate any perceptible displacement of the two consecutive images. While we can do much to adapt the movements of the subject to meet the needs of the two-color process, as much and more can be done in the matter of color. It should also be added that since it is possible to realize the complemental character of white with pairs of different filters, the color of light screens in the bichromatic process, is less restricted than in the three-color process. The importance of completing the white is moreover relative, since everything depends on the sensation of the eye, which receives the impression of white *Rome, Italy. G. Harry Brophy G. Harry Brophy, who for many years has been President of Local Union 253, Rochester, N. Y., died at the Strong Memorial Hospital in that city on December 9 after a short illness of pleuro-pneumonia. Funeral services for the deceased were held in Rochester on the night of the 10th, after which the body was sent to York, Penna., for interment. Brother Brophy was survived by his mother who resided in York, the birthplace of the deceased. G. Harry Brophy was one of the most popular members of the International Alliance, and in his many years of service to the Rochester Local Union he made a host of friends both in and out of the labor movement. The present strong condition of Local Union 253 is attributed by its members to the untiring efforts of Brother Brophy during his officership. from a % watt electric lamp, though it differs not a little from daylight, being much poorer in blue and violet rays, as we can note by observing a blue or violet colored object at night by artificial light. It may be said that the pair of screens used in bi-chromatic photography may be varied somewhat according to the subject and that while, in staged scenes taken by artificial light, it is expedient that the green screen should tend to blue, yellowishgreen screens are to be preferred for three color photography of open air scenes, the deficiencies in blue covering being counteracted by means of the complimentary exposure under white light. Illusion and Relief While we ask of the ordinary cinematograph to give our eyes the illusion of form and movement, color cinematography by whatsoever process it may be realized must give us a sensation that increases the illusion and approaches nearer to the truth; this does not depend entirely on the more or less faithful rendering of color, but also on the fact that, thanks to variety of coloring, the details of a picture, which would be merged in the usual chiaroscuro image, stand out. A color projection, though the colors may be but approximate, so long as they are the result of selection and are not merely applied by hand (as they were in the Pathe-Color process that has now well nigh died out) , affords not only the suggestion of color, but also of relief. And here it is fitting to make a comparison with the still projection of natural scenes, in which the effects of relief, atmosphere, and distance are considerably enhanced when the ordinary slides are replaced by colored slides obtained by the autochromatic, tri-chromatic, or bi-chromatic process. If it is true that the sensation of relief in respect of near subjects is in large measure due to binocular sight, it must also be considered that the effect of atmosphere and distance in a landscape is due entirely to the gradual training of the eye, whereby it transforms automatically, in the brain, the fading and variation of color into the sensation of distance. Thus, even failing the much desired invention of a stereo-cinematographic process (an invention that has been repeatedly heralded but the possibility of which seems remote, when considered apart from complicated systems of separate vision by the two eyes), the introduction of even approximate processes of color cine(Continued on page 40)