Practical Cinematography and Its Applications

by Frederick Arthur Ambrose Talbot

Water Beetle attacking a Worm.

One advantage of this system of printing is that the picture is printed with the camera with which the negative was obtained, and so first-class results are inevitable. The registration is assured as well as the alignment. In threading up the camera it is only necessary to make sure that the image on the negative comes squarely and truly before the window in the gate. Once this is so, every successive picture must be in perfect registration and alignment. There could be no method of printing more suitable for those who are travelling, or engaged on topical work, often under trying conditions, for the conversion from photographing to printing, and vice versâ, may be accomplished in an instant. Some of the more expensive cameras costing from £20 ($100) upwards are now fitted with a printing attachment, the printing accessory being detached when the instrument is being used for photographing purposes. These cameras follow where the Jury Duplex led the way.

The Williamson printer works upon a different principle, being a distinct and separate machine. Nevertheless it is an eminently practical appliance, and is as well adapted to the factory as to the amateur's dark room. It comprises a base board on which the whole of the mechanism is mounted, together with the stand for the light. ([See illustration facing page 84].)

In this installation there must either be a dark box to contain the light, against the face of which the base board of the printing mechanism is screwed, or else an aperture must be provided in the wall of the dark room and the light be placed on a shelf outside. The handy man, however, will be able to devise a light-tight box, either for the electric light or gas. In the latter case it must be fitted with a chimney with baffle plates absolutely light-tight, to carry off the products of combustion. The light-tight box should be lined either with absolutely safe ruby fabric, or with orange and ruby fabrics superimposed. If wood is used, the light-box is apt to split under the influence of the heat within.

The Williamson printer is of the simplest design conceivable. There is an upper spindle A ([see illustration facing p. 84]) on which the spool containing the negative is carried. Immediately below is another spindle carrying the spool B on which is slipped the coil of unexposed film. The negative film, emulsion side outermost, as it winds off the spool A is passed behind the guide roller C and then picks up the unexposed film of spool B. The emulsion side of the unexposed film comes into contact with the emulsion side of the negative film. Passing over another guide roller D the films pass together between the two rollers E to enter the gate F. The latter is mounted upon the rear face of a small chamber, the aperture of which is of the size of the cinematograph film image. This aperture is provided on the inside with a small hinged shutter. By opening this one can see that the negative image occupies the full space of the window, or make any other observations. The film is moved intermittently through the printing gate F by the sprocket wheel G, the teeth of which engage with the perforations in the films. The engagement of the films with this sprocket is ensured by the two pressure rollers H. The sprocket G is mounted upon and revolved by the handwheel I—a motor drive can be incorporated if desired—and after being moved beyond this sprocket wheel, the two films divide, the positive film being wound upon a spool or into its dark box, while the negative is wound upon another spool. The movement of the light K, either towards or from the exposure window F, is effected by means of the handle J, which has ten stops corresponding to as many different distances. The lamp moves to and fro along the support L.

It will be seen that the Williamson is a simple, straightforward machine. It is soundly constructed and works admirably. Its achievements are in every way equal to those of the complicated and more expensive model manufactured by the same firm for professional use.[2] So long as the machine works reliably, and has perfect registration and alignment, nothing more is required. Extra refinements, and little details, while of service to the expert, only serve to harass the amateur.

As a matter of fact the most important duties of a printing machine are to feed the two films evenly and easily through the gate, and to hold them flatly and tightly together, so as to secure perfect contact while they are before the exposure window. By this instrument both these duties are perfectly performed. The sprocket G continuously revolves under the steady turning movement of the handle, and the two films are held rigidly, tightly and steadily together by the pressure gate F.

Of course, in printing with this machine, the operator works in total darkness, owing to the coil of positive film being fully exposed. This is no handicap however, because the dark-room ruby lamp supplies sufficient light to enable the necessary operations to be performed. But it is not wise to use too powerful a ruby light, or the unexposed positive film will be fogged.