CHAPTER VII
PRINTING THE POSITIVE
Theoretically there is no operation in the whole art of cinematography which is more complex than the preparation of the positive. This is used for projecting the image on the screen, and is the result upon which popular criticism is passed. Also, in the process of printing the positive, several short-comings in the negative can be corrected.
At the same time, from the practical point of view, the preparation of the positive is simple. The beginner who has mastered the somewhat intricate process of development, need not apprehend any greater difficulties than those he has already overcome before he essays to print his positive. In practice he will soon become proficient, though he may retain rather hazy ideas of the theory of the matter.
The essentials for the preparation of the positive are a printing machine and an illuminant. The appliances and methods of operation differ completely from those used in any other branch of photography, so that a new art virtually has to be mastered. Fortunately, the beginner gets assistance from those masters of the craft, who, having left the producing for the manufacturing side of the industry, willingly give advice to the tyro. By following the few rules which these early workers lay down, the beginner will not go far wrong, and will not run the risk of incurring many dispiriting failures. While the large professional firms use elaborate and costly printing machines, the amateur is able to get just as good results with simpler and cheaper apparatus. He could not wish for a better equipment than the Williamson printer, which costs only £4 10s. ($22.50), or the Jury Duplex, which is a combined camera and printer.
So far as the illuminant is concerned this depends upon circumstances. In most towns it is possible to obtain electric light, which is the simplest, and taken all round, the most reliable and satisfactory illuminant. If this is not available, gas and an incandescent mantle may be used. Failing either of these conveniences, acetylene or petrol gas, the latter with the incandescent gas mantle, can take their place. Even daylight may be used.
Success in printing depends upon a correct judgment of the intensity of the light, and of the density of the film. This enables one to estimate the exposure required. Obviously this knowledge can only be acquired in the school of practice. The same experience is needed to estimate the length of the exposure in making lantern slides, or in bromide printing. But it must be borne in mind that in the cinematograph film one is working with a much more sensitive emulsion.
A very good practice for the beginner is to make experimental exposures with short lengths of film—say 12 inches—making the tests with sections of the negative which vary in density, at various distances from the light, and at different speeds. A careful note should be made of each trial. In this way one can estimate the exposure and learn how it should be varied at different points of the negative where the density varies. Moreover, the knowledge will be acquired at comparatively little expense.
If the negative has been over-exposed or over-developed, or both, a common error in the first attempts, it will naturally be very dense, and will demand a longer exposure, or a more powerful light, than a negative which is exposed correctly. This situation may be met either by slowing down the process of printing, or by bringing the light nearer to the film. On the other hand, if a negative is under-exposed it had better be destroyed at once, as it is worse than useless. An over-exposed negative will yield a passable print, possibly somewhat harsh, but nothing can be done with a negative which is deficient in detail. The only exception that may be made to this drastic policy is the topical film, which may have been taken under adverse conditions, during a fog, or in heavy rain, or on a dull day, or at a late hour when the light was bad. In the topical film it is more the interest of the event than the quality of the film that is important.
For absolute simplicity it would be difficult to excel the system adopted in the Jury Duplex camera. In this case one obtains both camera and printing apparatus—without the lens—for the modest outlay of £8 ($40). There is a small bracket mounted upon the outer top face, and near the front edge, of the case. This bracket carries the spool on which the negative film is coiled. This is slipped on the bobbin and locked in position by means of a small lever. The film is carried from this spool between two small guide pressure rollers and fed into the camera through a slot faced with velvet, like that provided in the dark boxes. The film is pulled down a sufficient distance to enter the gate so as to secure engagement by the claws of the camera mechanism. In threading the film care must be used to bring the emulsion side facing the dark boxes and the glossy side facing the lens.