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Process
Positive Film
# DU RING the past few years, the number of amateurs using positive film for their title making has been increasing steadily. There are two principal reasons for this increased popularity of positive film. First, it affords an easy method of making titles that show white letters on a black background and second, it is by far the cheapest method of making titles.
Sixteen mm. positive film can be bought at about one-fifth the price of any standard brand panchromatic film and 8mm positive film costs less than one-half the price of the regular reversal 8mm film.
Positive film not being color-sensitive is from three to four times slower than panchromatic film and therefore can be easily processed by t h e amateur in a makeshift darkroom. Many amateurs have made their bathroom into a temporary darkroom because of the running water and the fact that there is usually only one window to be sealed up. The fact that positive film isn’t color sensitive makes it unnecessary for the developing to be done in the absolute dark ; a safety light, red or green, can be used without affecting the film.
In making titles directly on slow positive film stock the greatest possible contrast is desired. That is you desire the letters to be a pure sharp white against a dense black background. To accomplish this a developer should be used in which the contrasty developing agent predominates. In motion picture developing solutions there are two developing agents (Metol and hydroquinone) . One of these, the metol, is a rapid working developer and gives a soft, un-contrasty, flat image ; the other, hydroquinone, works slowly and gives more pronouncement to shadows and the gradations that exist in the shadows. Also, found in every developer is an alkali. The function of the alkali is to accelerate the action and thus produce strong contrast in a shorter time. The caustic alkalis are
7
mg
by
A. C. Bell
35mm
the most commonly used and among these sodium carbonate, which is ordinary purified washing powder, is the most popular.
Thus the best developer for positive film titles should contain as a developing agent, predominately hydroquinone; and should contain a strong caustic alkali (sodium carbonate) to speed up the action.
Following these pointers the following formula which will cost you about fifty cents a gallon has been found excellent for positive film titles. At 65 degrees Fahrenheit this solution will properly develop your film in five minutes.
Metol 18 gr.
Sodium sulphite 5 1/3 oz.
Hydroquinone . -352 gr.
Sodium carbonate oz.
Potassium bromide 50 gr.
Citric acid 40 gr.
Potassium meta bisulphite 90 gr.
Water 1 gal.
IN doing this processing at home you will need a developing tank if you intend to develop long lengths of film. These
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