American cinematographer (Jan-Dec 1927)

Eighteen AMERICAN CINEMATOGRAPHER June, 1927 Setting the pace for filmdom IN the past, it has been the cinematographer's privilege to lead the way. Due largely to his efforts, the motion picture is now regarded as an art as well as an industry. There is no reason why he should not continue to lead. For Cooper Hewitt lighting, which has never failed to supply him with artistic lighting effects, is keeping pace with studio requirements. Continue to rely on the "Coops"! COOPER HEWITT ELECTRIC CO. HOBOKEN, NEW JERSEY Western Distributing Points KEESE ENGINEERING CO. Hollywood — 7207 Santa Monica Blvd. San Francisco — 77 O'Farrell Street 22i ©C. H. E. Co., 1927 Roy Davidge Film Laboratories An Exclusive "Daily" Laboratory Panchromatic Negative Developed With a Minimum of Grain 6701 SANTA MONICA BLVD. HOLLYWOOD 1944 Supersensitive Lighting Equipment CRECO for Supersensitised and Pan Stock Experiments have been made with the addition of remove the oil with carbon tetrachloride and then give the film a second treatment with a mixture of denatured alcohol or tertiary butyl alcohol and water in the proportions outlined above. This involves more labor but is a very satisfactory procedure. Practical Recommendations 1. For cleaning the base side of negative and positive film after processing the following solution is recommended : Ammonia (Cone.) 5 parts by volume Water 95 parts by volume Alcohol* to make 1000 parts by volume •The "Pyro" brand of denatured alcohol of the Industrial Alcohol Company is satisfactory, although isopropyl alcohol or tertiary butyl alcohol are to be preferred. The solution may be applied to positive film by means of a cleaning machine and to negative film when wound face down onto a cloth covered drum. Negative film may be cleaned with safety on certain types of sprocketless cleaning machines, but it should not be handled on machines with sprockets owing to the possibility of damage to the film. 2. In order to remove dust and finger markings from negative film it should be cleaned before printing by wiping gently with silk plush moistened with carbon tetrachloride (sulphur-free) as it is being wound on a rewinder. An electric fan should be arranged so as to blow a current of air across the film in a direction away from the face of the operator. The cleaning process should be repeated after every third or fourth print has been made. 3. For cleaning film which has accumulated oil and dirt during projection, carbon tetrachloride (sulphur-free) as supplied by the Dow Chemical Co., is recommended. For cleaning brittle film the following solution at the same time removes oil and moistens the film, thus tending to restore its flexibility. Carbon tetrachloride 10 parts by volume Water 20 parts by volume Ter. butyl ale. to make 100 parts by volume The quantity of water in this formula should be varied according to conditions. If the film is too moist after treatment less water should be used in the formula and if too brittle more water should be added. In this case it will be necessary to increase the quantity of alcohol also so as to retain the water in solution. The cleaning liquid may be applied to the film in the same manner as outlined under (2) above. This method is not always satisfactory because if the solvent does not evaporate thoroughly before the film is rewound, more or less solvent is retained between the convolutions of the film and in case an impure solvent is used this will be liable to attack the film image on storage. A film cleaning machine of the type recommended by Faulkner2 is to be preferred. In the case of very brittle film two successive applications may be necessary. The odor of tertiary butyl alcohol may also be objectionable in hot weather. An alternative procedure is to first remove oil from the film with pure carbon tetrachloride and then moisten the film by passing through a mixture of denatured alcohol, isopropyl alcohol, or tertiary butyl alcohol with 15% to 25% of water.