Home Movies (1943)

PRINCIPAL STEPS IN NEW JEPSON HOME REVERSAL PROCESS • Secondary steps involve washing, sulphite bath and fixing and hardening. Chief advantage offered is ability to compensate for exposure errors without sacrificing tonal quality. A MEW HOME KEVERS.IL PROCESS By STANLEY (EPSON, A. R. P. S. Sec'y-, Amateur Cine Society of India i^.FTER a great deal of experiment, I have worked out a successful rew home reversal method which gives softer results on positive film stock, and permits the darkroom amateur to exercise a greater degree of control over errors of exposure. Trade laboratory processing provides for a measure of compensation in reversing poorly exposed films, but the inability of the amateur to readily compensate for under or over-exposure in the usual home reversal method has caused many to abandon the idea of processing their own films. This new method is essentially different from the orthodox reversal technique and in brief it amounts to printing the negative image on to the unfixed portion of the emulsion beneath it; the negative image then being dissolved in the usual reversal bath of acidified bichromate or permanganate. Before enumerating the many advantages inherent in this new method — which, to avoid confusion, I will call the Jepson reversal method, (though I have no desire for it to be known by that name!) — I will briefly outline the process: In the darkroom, the exposed film must be placed on a solid drum without any protuberances such as pressure bars, etc. An open developing rack will not do. With this system the film must be kept tight upon a solid drum so that no light will reach the back of the film and thus cause it to become fogged. To further insure against fogging, the drum surface should be painted black. If the amateur desires to reverse a short test strip of film, he can do so by winding the film around a wooden cylindrical support of a size that will fit irto a large jam jar which will serve to hold the processing solutions. And if the round wooden support is attached to lid of the jam jar, it will be easier to handle and make an excellent quick developing apparatus for test films. The film is then developed in any ordinary negative developer, and in making tests, the temperature and time should be watched closely. The degree of development should be to a low gamma, the sort of negative which will yield a nice soft print. Apart from time and temperature, one suggested method of control is to stop development as soon as the image appears on the reverse of the film. The correct density is important in relation to printing time. Now wash the negative for a minute or so. If the temperature is high, subject film to a chrome alum stop bath for half a minute. Empty the drum trough and prepare to print this negative on the undeveloped emulsion below. The exact exposure can easily be ascertained by a test strip laid flat on a piece of black paper with varying exposures as is done in the case of testing bromide paper. I have found that from 15 to 30 seconds (according to the density of the negative) is required at a distance of 4 ft. when using a 60 watt bulb. If the film is on a drum and only one-third of the drum is exposed to light at once, then naturally the 1 5 seconds exposure allowed a test strip will have to be extended to 45 seconds for the revolving drum. This is because only one-third of the circumference of the drum is exposed to an overhead light. I have tried getting off surplus moisture from the film before printing by speedily rotating the drum and then wiping the film surface with a chamois. I have also made prints while the film was turning and washing in water with a complete film of water over the emulsion. I have not noticed any difference, but I recommend wiping the surface moisture from the negative. Obviously, spots of water should not be allowed on the surface of the negative. The remainder of the process is completed under the darkroom red light. This consists of removal of the silver negative image in the ordinary bath of potassium bichromate acidified with sulphuric acid, or with acidified potassium permanganate. I do not propose to bur• Continued on Page }/2 360