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.
1950 SIMPLIFICATION OF PROCESSING METHODS 21
Mechanical Condition of Processed Film
A marked embrittlement of a type which is not removed by equilibration with an atmosphere of 70% relative humidity is observed occasionally when radiant heat is used improperly in drying. The condition appears to be caused when the film reaches an excessively high temperature in the course of drying and can be largely corrected by rewetting the film and drying it under more favorable conditions. It is not a direct consequence of rapid drying but rather of overheating during drying.
Almost all of the heat which goes into the drying process is accounted for as the latent heat of evaporation of the water so that, unless evaporation is retarded by the accumulation of moisture vapor above the film surface as a result of insufficiently high velocity of the drying air, a high rate of heat input produces only a moderate rise in temperature of the film. Therefore, a first concern in designing a drying system is to have proper velocity and distribution of the air. Only when this is assured is it safe to introduce the large amount of heat which will be required for rapid evaporation of water.
Effect of Rapid Processing on the Film Support
Up to the present time, no detrimental effects of rapid processing on the film support have been observed when temperatures and physical handling were reasonable. As the temperature actually attained by the film is raised above 125 F, additional care is required to limit the tension applied because the film becomes more susceptible to plastic deformation.
ADVANTAGES IN USE OF RAPID PROCESSING
Some of the advantages obtained by the use of the rapid processing technique are as follows:
1. Elimination of delay in obtaining completed film.
2. Simplification of equipment design, which affects construction, maintenance and use.
3. Reduction of volume of baths, especially if spray application is used, thereby reducing the amount of space required and simplifying chemical control.
Some of the disadvantages of the methods considered are :
1. Increased chemical consumption in certain cases where concentrated baths are replenished rapidly.
2. Increased power consumption when certain extreme requirements as to operating characteristics or size are imposed.