The motion picture projectionist (Nov 1931-Jan 1933)

June, .1932 Motion Picture Projectionist 13 photography — and the motion picture art — possible. The silver bromide and other silver salts of the emulsion are very much more sensitive to light than the silver nitrate from which they are derived. Silver nitrate Is therefore merely a raw material for the emulsion-makers when they carry out the next stage of making emulsions; but the care taken in making silver nitrate, so briefly sketched here, assures the emulsion department that its most important raw material is reliable. Precautions for Cleanliness Tall chimneys are necessary — 366 feet tall in our typical plant — to carry any fumes and soot high into the upper air whence they will blow away far from the manufacturing confines. Fumes evaporated off in the process of making silver nitrate are thus disposed of. Similarly, what soot leaves the power houses after efficient burning of the daily 500 tons of coal goes into the chimneys. Well are these precautions, for no man in this very large industry knows which particular ten or twenty feet of negative may catch the "shot" of a lifetime. Even if it were not of paramount importance to have the many millions of feet running through studio cameras and theater projectors perfect, it would be necessary to take unlimited pains to avoid flaws if only to be sure that the film should not fail the great opportunity that may come to a cameraman only once in a lifetime — perhaps a unique news scene, or a hazardous plane crash by a double, or even the record of a fleeting glance that wins the public to some sensitive star. How the film industry has progressed in its safeguards for film cleanliness and quality and stability may be observed in the department of our typical plant where the emulsion is coated on the transparent, flexible film base. There may be veterans still active in the motion picture industry whose memory extends back far enough to give them perspective on the resulting film improvement. Coating the Film For something like ten years after George Eastman began the manufacture of film in 1889 the process was to form the film base, and then to coat it with the emulsion, on a long plateglass table. It is obvious, in these days of 1,000-foot reel lengths, that 1,000-foot tables would be impractical; but the machine age of film-making has conferred much greater benefits than the additional lengths possible. The close control of the emulsion coating process resulting from continuous machine operation has been important principally in yielding more ^perfect film. In other words, control of the conditions, including atmospheric conditions, under which the emulsion is applied to the film base is a positive manufacturing factor in addition to its perhaps negative importance in keeping anything from going wrong. In the glass-table stage of film manufacture, whatever air happened to be in the room was good enough to dry the film regardless of dust or the weather outside — with what results in the way of perfection most of us can remember from the nickelodeons. Now, instead, an elaborate and modern system admits to the coating machines only air that has been washed, filtered, and brought to exactly the proper temperature and the right degree of moisture content. The enormous refrigeration plant of our typical film manufactory is important in doing that. In the interest of cleanliness, even the many miles of copper air ducts in the basement below the emulsion coating machines are frequently flushed and polished, and the air comes into the system through filter Machine attendants of course wear white laundered suits and caps. These rooms, where daily miles of film are coated in the dark, are cleaner than hospitals or bakeries, to say nothing of other industries where daylight penetrates. Motion picture film is 35 millimeters wide. That sounds simple enough, an absolute fact; and so it is. Projectionists need not concern themselves about it. But an exact film width is not heaven-sent, any more than money grows on trees. If the film were not exactly 35 millimeters wide — any foot of it — there would be no insurance against trouble in the projectors. Somebody in the typical film manufactory had to worry about the width, or projectionists would be worrying instead. Leaving out of consideration the history of how the 35-mm. standard was set, we shall find by inquiry that cutting the film to the prescribed width once was a major problem — until it was solved. Like a thousand other details in making film, which is probably the most delicate product manufactured on a huge modern scale, the problem of exact-width slitting was solved and became just one more factor in justifying the adage that "trifles make perfection." oi^ • Chemical Stages in the Manufacture of Photographic Fihn EASTMAN KODAK •Jl. .. • WSm The Evolution of Film from Raw Material to Finished Product