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.
46 Transactions of S.M.P.E., Nov. 1924
The Relative Temperatures of the Various Solutions
In high temperature work it is important that the temperature of the various solutions should be maintained as nearlj constant as possible, that is, the temperature of all the solutions should be equal because if a swollen film is subjected to a sudden change of temperature, for example, if it is removed from a hot solution to a cold one and vice versa the gelatine film is subjected to strain and a leather-like graininess of more or less coarseness will appear all over the film which effect is known as reticulation. Recent experiments have shown that excessive graininess of film finished in hot weather is a mild form of reticulation. The effect of a sudden change of temperature is a maximum when the film is excessivel}^ swollen and a minimum when unswollen and hardened. Several procedures, therefore, are possible as follows:
A. Maintain the temperature of all solutions equal to that of the wash water.
B. Use a cool developer and warm hardener, fixing bath, and wash water.
C. Use a cool developer and hardener and warm fixing bath and wash water.
All the above give good results though C. is the best procedure if cooling is possible. The wash water may be either hot or cold, that is, once the film is tanned in the unswollen condition it will withstand sudden and severe changes of temperature without reticulating.
Drying of Film at High Temperatures
The usual difficulty encountered when drying film at high temperatures when high humidities usually prevail is a result of excessive swelling of the gelatine which, therefore, contains an excessive quantity of water. If swelling of the film is prevented by the above recommended procedure, drying will be rapid and can be hastened by raising the temperature of the drying air which in turn raises the relative humidity without danger of softening the film emulsion. Rapid changing of the air in contact with the film surface is also of importance.
In the field, a mosquito netting cabinet is necessary to prevent access of insects to the film.
Excessive graininess of the film which is often produced by slow drying at high temperatures of excessively swollen film, does not occur if swelling of the gelatine is prevented as explained above.
Effect of Hardening on the Wearing Qualities of Negative and Positive Film
Experiments have shown that the wearing qualities of film processed in the above manner are not materially affected as a result of the excessive hardening with chrome alum. If the gelatine coating,