American cinematographer (Aug 1933)

American Cinematographer • August 19 65 1-90 HE negative-positive system unquestionably offers many advantages to the 16mm. worker—especially the ability to make fresh prints at any time, at a moderate cost. Unfortunately, however, it has also gained the reputa- tion of being undesirably grainy—which in the minds of many users more than offsets the advantages offered Since inquiry shows that most 16mm. negative film is coated with the identical emulsion used for the same manufac- turers’ highly successful 35mm. product, this writer has fre- quently doubted the justification of this reputation. The 16mm. picture is, roughly speaking, about half the size of the 35mm. image; it is rarely subjected, in projection, to any enlargement even remotely comparable to the tre- mendous magnification generally practiced in our larger theatres; and even though the 16mm. audience is often much nearer the screen, proportionately, than is the the- atrical audience, why should the graininess of the two identical emulsions be so greatly disproportionate? Careful consideration of the problem will show that the only point in the lines followed by 35mm. and 16mm. film from factory to screen, at which there is an appreciable de- gree of divergence, is in the developing laboratory. It must be admitted that few commercial film laboratories are in a position to be so painstaking as are the specialized plants devoted to the processing of a studio’s negative. It is like- wise well known that the grain-producing characteristics of different developing solutions vary considerably; and, further, that those producing the finest grain are as a rule more ex- pensive, and require more care in compounding and man- ipulation than do the more familiar ones which produce a larger grain. Such being the case, the only solution to the problem was obviously to experiment personally with 16mm. negative and a variety of the fine-grain developers recommended by the various research engineers. The results have more than justified the experimentation, for the finest-grained results produced have shown that 16mm. negative film, properly processed, will give results absolutely comparable to re- versal emulsions. Compared with reversal film by simul- taneous projection on a ten-foot screen, I have found little or no difference in grain characteristics between comparable scenes made with the same equipment on reversal and nega- tive films. The equipment used for processing negative film, while important in itself, is of less importance than the develop- ing solutions used. Almost any method will suffice—pin- racks, Stinemann racks, “Correx” apron-rolls, or (in the case of short lengths) revolving drums—so long as the operative procedure is correct. Since the majority of cine-amateurs have had more or less experience in still photography—including developing and printing—it is hardly necessary to state that negative development requires two chemical solutions—the developer and the fixing-bath—and at least two (preferably three) intermediate washings in cold water. The best method is to put the film on the rack, immerse it for a few minutes in cold water (this promotes better and more uniform chem- ical action, and retards the formation of air-bubbles) ; then immerse it for the required time in the developer, agitating it by lifting the rack up and down a few times immediately on immersion, and also several times during the developing process; then immerse the film again in cold water, to clear away the developer before immersing in the acid hypo fixing-bath; then, after fixing for eight to ten minutes in the typo (the regular Eastman Acid Hypo is excellent for this purpose) , wash in running water for at least twenty minutes, and dry. All operations up to and including the first minute or two in the Hypo should be done in total darkness. Throughout all of these manipulations, three things are of Fine Crain Enlargement from 16mm. negative devel- oped by ordinary commercial laboratory. Note greater graininess. Both illustrations made on DuPont Panchromatic 16mm. Neg- ative film, with same camera and lens. Enlargements by Cilbert Morgan. paramount importance: absolute cleanliness; protecting the film from any dirt or chemical impurities (for which reason distilled water and filtered solutions are always preferable, though in some localities the regular tap water may be ade- quately pure. Tap water can, of course, be used for the washing.); and thirdly, protecting the film from anything which might scratch or mar the soft emulsion. All of the solutions, too (including the rinsing-water) should be kept cool, between 65 and 70 degrees Fahrenheit, so that the emulsion will not be unduly softened. All solutions should be kept at as nearly uniform a temperature as is possible. As far as the developing solutions themselves are con- cerned, the production of truly fine-grain results demands highly specialized developers. It is true that motion picture film can be developed in any solution that can be used for ordinary still photographic negatives; but this is not de- sirable: for really good results, it is imperative that the formulae specifically devised for cine-film processing be used. It must be remembered that the problems involved in still photography and cinematography are decidedly different. One of the most outstanding if the features which differ- entiate the two is the vital importance of grain-size. The tremendous enlargement demanded of a motion picture image is many times more exacting than anything normally demanded is still photography. In the latter, we rarely go beyond an 11x14 inch print: and even when miniature- camera negatives are used, the enlargement is in no way comparable to that involved in projecting 16mm. picture- less than Vz inch square—onto a five or six foot screen. (And it must be remembered, too, that with modern equip- ment many users of 16mm. employ screens ten feet or more in width.) Professional experience has proven that we can only go a certain distance in this direction before being stopped by the fact that the grain of the emulsion becomes enlarged to the point of objectionable visibility. Scientific investigation has proven that the grain in posi- tive film is so small as to be negligible: accordingly, any steps toward fine-grain results must be taken with the nega- tive. Normally speaking, the actual grain-size of either 35mm. or 16mm. negative emulsions is such as to be within satisfactory limits. Unfortunately, however, many develop-