We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
GENERAL PRINCIPLES 21
It is obvious that enlargements of the negative may be produced by placing the film not in contact with the paper, but in a projector rather similar to an optical lantern, and throwing an image of the negative onto a large sheet of sensitive paper. More detailed information will be given concerning the processes of development and fixation when the operation of continuous motion picture processing machines are considered.
The Requirements of Motion Pictures A Brief Historical Survey In order fully to understand the modern cinematograph camera it is necessary to trace its development from those early inventions which may now appear to be extremely simple. Much research work has been done in an endeavour to establish the exact history of cinematography and, as is well known, many inventors have contested their claims in this connection. The following survey in no way pretends to unravel this problem it is merely concerned with the development of basic principles. However, it must be remembered that, at the time of their inception, these inventions were looked upon as nothing more than ingenious novelties by a public which had only recently accepted the marvels of the optical lantern.
Motion pictures would never have been possible but for a particular characteristic of the human eye. This characteristic is known as 'the persistence of vision', or retention of image, and is best described by the following experiments and examples of modern devices which, like the motion picture, depend upon this peculiarity.
If a glowing cigarette is taken into a darkened room and whirled around in a circular path, an observer will see a continuous glowing circle of light. It is quite obvious that no such circle actually exists and yet, due to our inability to 'forget' immediately the light given by the cigarette after it has moved to another position, we continue to 'see' the glow until the cigarette again returns to that position during the next revolution of the hand. By such time, of course, the impression which will then be fading -is again stimulated and thus the eye appears to see a continuous circle. This effect is most conveniently expressed by Hopwood as follows: — 'We continue to experience the visual effect of light after it ceases to act'.
A modern example of this is found in the Neon directional arrows used to indicate the entrance to some cinemas, etc. Two neon arrows are mounted in the same plane but are displaced in the direction indicated by the arrow heads. Each arrow is illumi