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.
PROCESSING EQUIPMENT 103
in the initial threading, all the racks are loaded to a position a few inches above the lower extremity, this will cause the spring 'H' to pull arm 'J' downwards. This anti-clockwise motion on arm 'J' will increase the drive to the second rack and so increase the speed at which the film is removed from the first rack.
Obviously, a balanced condition will eventually be reached in which the tension drive to each rack has been automatically adjusted to bring it in line with the neighbouring racks. The third lever on each tension adjusting assembly is merely to provide a counter-weight to the mass of the roller 'E'.
Methods of Developer Agitation
One of the major problems with the early continuous processing machinery was to obtain uniform development. Naturally, if the film were to move through a static developing solution, a condition known as 'developer drag' (see later chapters) would be created and very uneven photographic densities would result. This is because very localised amounts of developer would more or less remain with the film during its passage through the solution, would become exhausted and would have a reaction upon neighbouring portions of both film and developer.
This type of 'directional effect' can be overcome by employing agitation in the solutions to prevent exhausted pockets of developer remaining with any one portion of film. Agitation merely by pumping solutions through the bath is sometimes inefficient and many modern machines use some form of developer spray.
For example, in the Spoor-Thompson processing machine, only the lower rollers in the developing racks are actually immersed in solution, but fine jets of developer are sprayed onto the strands of film as they pass through the racks. Other modifications are to insert a pipe carrying a series of jets into the base of the solution tank and to spray the solution 'through itself this creates a very high degree of agitation and also maintains a good solution level covering the main body of the film racks
Film Squeegees
In the 'demonstration model' we have discussed the use of compressed air jets to squeegee the surplus water from the film before it enters the drying compartment. Surplus water is also sometimes removed by using rubber squeegees to mechanically press the water from the film although, of course, there is always the chance of scratching the film if foreign matter should become lodged within the rubber 'jaws' of the squeegee.