International projectionist (Jan-Dec 1940)

for color work. It is well known that the passage of light through the cellulose base and three-color film surfaces not only diffuse and refracts the light but seriously reduces its velocity. We have found that a color print on metal with its high reflecting surface gives a more luminous image on the screen than is obtainable with the ordinary color film now in use. Coating, printing, developing and projecting from metal film are based on fixed physical factors, and the making of ■color film can be likewise standardized. Our statement in a recent issue of a -widely read weekly magazine that cellulose film would not last for 20 years was challenged by one of the distinguished scientists in the photographic field. In our answer, we produced such overwhelming evidence that we believe this phase of the controversy to be now closed. To the many librarians, government officials and technicians, we convey our regrets that we were forced to insist on the fact that cellulose films were not to be depended upon for permanent records. We submit that all unbiased .scientific investigation has established the fact that cellulose film should not te used where an endurance of over ten years is essential. It is gratifying to know that valuable cellulose negatives now in existence may be printed on metal film with the positive assurance that they will endure indefinitely. Those engaged in aeronautical photography have been concerned with the adaptation of metal film for their purpose. We propose to produce an 8-inch roll of metal film in 500-foot lengths that will not exceed 16 pounds in weight. With a positive emulsion, this may be developed in the air and calculations carried out with the utmost accuracy based on the fact that the metal expands and contracts equally over the entire surface. We have taken positive prints on a roll of metal with a positive solution, exposed the same, and secured the finished print in less than three minutes. Photographic development on a metal film is confined exclusively to the emulsion. In amidol or metol hydroquinone, development takes place in less than two seconds washing; fixing may be done in 60 seconds; and final washing and drying over any heated unit in a further 60 seconds. We find the results of the print are permanent and almost grainless. In case of fire, the image is not destroyed until the heat reaches the melting point of the metal. In conclusion, it is necessary to deal briefly with the great number of in quiries from persons using 6 mm. film. This is of special interest to us, as we believe the intimate records of childhood and the valued records of science and business deserve a permanent photographic medium. We are developing as rapidly as possible machines for projecting 16 mm. metal film, since we are convinced that the high costs in this field will be considerably reduced with the use of our film. This feature together with the facts of positive non-inflammability and permanence offers professionals and amateurs in the 16 mm. field something to look forward to with keen anticipation. It is particularly gratifying that metal film makes a major contribution to the field of sound recording of voice, music and all phases of sound reproduction. The sound track on our highly reflective metal ribbon has proven to be ideal for the reproduction of radio programs. Both sides of the film may be used and as many as ten tracks may be printed on each side, thus giving 200 minutes of sound recording on 1,000 feet of film that weighs 6% pounds and takes up a space of 8 by 1% inches. One of the major applications for metal film is in the field of permanent record. The opportunity now presents itself to record imperishably the word and deed of our living great, distinguished • men and women in the fields of science, literature, medicine, politics and the other ranges of human endeavor. What would we not give if we could see and hear the immortals who have made their impress upon the history of American civilization. The utmost which our forefathers could do was to record their words and actions by means of books. Current Technical Opinion on Metal Film APROPOS the accompanying paper anent metal film by Dr. R. W. Carter is the circumstance that several years ago International Projectionist had occasion to submit to ranking laboratory technicians in the motion picture industry samples of metal film for examination and comparison with nitrocellulose film. Their findings at that time (1934) were as follows: (1) The loss of light during projection would be almost prohibitive and, to make a rough guess, under any given conditions, the screen intensity would be only about 1/50 that existing when projecting by transmitted light with the usual motion picture film. (2) If the metal film becomes buckled, it remains so more or less permanently. (3) The edges of the perforations have no resiliency, so that they are much more readily distorted by the sprocket teeth than with nitrocellulose film. • Problem of Splicing (4) It is doubtful whether the degree of adhesion of the emulsion to the film would be satisfactory. (5) It would appear to be extremely difficult to splice the film satisfactorily. The manufacturers have not suggested any method of splicing. (6) With highly alkaline developers, it is probable that the aluminum would be attacked, and also, prolonged fixation in a fairly acid fixing bath containing silver salts would cause the deposition of silver which would tend to impair the high reflecting power of the aluminum surface. Coincident with preparations for publication of Dr. Carter's paper in this issue, I. P. requested these same labora tory technicians to review their findings of several years ago on the basis of the generally admitted progress of metal film in the intervening period. Their answers may be summarized thus: • Current Qualified Opinion The findings embraced by the foregoing Items 1 to 6 are essentially correct, although Items 4 and 6 may not apply to the latest type of metal film and should be ignored on the assumption that, apparently, the metal strip is not coated with a gelatin film. With regard to Item 5, it is stated with great emphasis by the proponents of metal film that a satisfactory "special cement" has been developed which will give "satisfactory" results; but it would be extremely interesting to a large majority of technical workers in the industry to have tests made to determine the strength of such splices. This, then, is the pro and the con of the discussion relating to the comparative merits of metal and of nitrocellulose film. In the absence of any positive proof tending to prove the assertions made on both sides of the fence — without which, of course, no judgment can or should be passed thereon — it occurs to I. P. that it might prove invaluable to the motion picture industry to arrange a symposium wherein all aspects of the matter could be considered thoroughly and in an impartial manner. The S. M. P. E. would seem to be the logical body to arrange such a meeting, particularly since the next Convention of the Society will be held in Hollywood wherein are located technical experts on just such matters as are at issue in this case. — J. J. F. 20 INTERNATIONAL. PROJECTIONIST