American cinematographer (Jan-Dec 1924)

Twenty AMERICAN CINEMATOGRAPHER November, 1924 of the film caused by too rapid drying of the film. Buckle may be prevented by slow drying and taking care that the film is not subjected to tension during drying. Buckled film may often be restored by re-subjecting it to a humid atmosphere. 3. Fluctuations of Background Density. This is caused either by unsteady cranking or fluctuation of intensity of the title card illuminator. Mercury vapor lamps should be allowed to burn from ten to fifteen minutes before commencing work in order to attain maximum intensityFluctuations in the line voltage should be carefully guarded against 4. Camera Static. This is often a result of excessive tension or friction in the camera. The relative humidity of the title making room should be not less than 60% to 70%. Obstinate cases may be overcome by allowing the film to remain over night in a humidor though excessive humidification of the film will cause sticking and buckling in the camera. 5. Unsteadiness on the Screen is a result either of unsteadiness in the camera mechanism or lack of rigidity of the camera support. 6. Lettering is not Parallel with Frame Line. Title card w'as not level during taking. The best method of insuring parallelism of frame line and lettering is to sight along a horizontal straight edge fitted to the top of the camera. (The End) (Continued from page 4) A. Thoroughly dry out a quantity of clean paper by heating in an oven and pack loosely in a box fitted with a tight lid. Place the loosely wound film in the center of the dry paper and allow to remain over night. The desiccated paper rapidly absorbs moisture from the film and should be redried daily. On removing from the drying box, repack the film immediately. B. A more rapid method of drying the film consists in placing the film in a container together with calcium chloride, which rapidly extracts moisture from the surrounding air. Calcium chloride is supplied commercially either in sticks or as porus lumps which pulverize when shaken so that if the chloride were placed in close contact with the film, fine particles of dust might be shaken onto the film, while in time the calcium chloride liquifies and this might also run on to the film. It is better, therefore, to use pumice or asbestos wool impregnated with the calcium chloride so as to prevent possible injury to the film by the pulverized or liquid chemical. Thoroughly soak the broken pumice or asbestos wool in a saturated solution of the calcium chloride and then dry out thoroughly on a shovel or a piece of sheet iron over a fire; place the pumice on the bottom of a wooden box or metal can and support the film over this on a suitable perforated shelf. A convenient drying box is made by soldering together two motion picture film cans back to back and then perforating the base now common to the two cans. The absorbent material may then be placed in one section of the twin can and covered with a little absorbent cotton and the film placed in the adjoining section. When the pumice or asbestos wool loses its desiccating property by becoming moist it may be restored by reheating over the fire, and this process may be repeated indefinitely. Although in the larger motion picture laboratories it is possible to control the temperature of all developing solutions, many small laboratories have no equipment for cooling so that it is necessary to work with solutions at existing temperatures and wash water as high as 90°F. It is, ■^j SPEED! SPEED! SPEED! The Bausch & Lomb Ultra Rapid Anastigmat is an f:2.7 lens. This not only is its rated speed, it is the speed at which it actually performs. Bausch G§P Lomb Optical Co. Ne<w York San Francisco Washington Chicago Boston Rochester, N. Y. London CRECO FOR RENT! Bell & Howell Cameras COMPLETE EQUIPMENT 40, 50. 75 M. M. Lenses 170 Shutters J. R. LOCKWOOD 523 North Orange St. Phone Glendale 336 I -W Glendale, California Cinema Studios Supply Corp. 1438 Beach wood Drive Holly 0819 LIGHTING EQUIPMENT FOR RENT L. A. FIRE DEPARTMENT WIND MACHINES Water Engine