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.
SOME PROPERTIES OF CHROME ALUM STOP BATHS AND FIXING BATHS (PART II)*
J. I. CRABTREE AND H. D. RUSSELL
PART II. CHROME ALUM FIXING BATHS
INTRODUCTION
The desirable properties of chrome alum fixing baths are analogous to those of potassium alum fixing baths as outlined in a previous paper.1 A satisfactory bath should have the following properties: (1) It should fix the film sufficiently rapidly and should have a fairly long fixation life; (2) the bath should harden the film to a sufficient degree and should maintain its hardening properties either with or without use; (3) it should not sulfurize prematurely at temperatures below 85°F.; (4) the propensity of the bath to deposit a sludge on the addition of developer should be a minimum ; and (5) there should be a minimum tendency to produce blisters even when used in conjunction with a strongly alkaline developer.
Previous work with chrome alum fixing baths in this laboratory has been confined to the compounding of baths suitable for use at high temperatures and a satisfactory formula which maintains its hardening properties even with use over a period of one or two weeks has been recommended.2 At normal temperatures, however, when used in a deep tank such a formula tends to harden the film to an undesirable and unnecessary degree, and is relatively expensive.
In order to compound an efficient chrome alum fixing bath formula for motion picture work at normal temperatures it was attempted to study the various properties of a mixture of chrome alum, sodium sulfite, an acid, and hypo, in a manner similar to the methods used to study the properties of aluminum alum as described in a previous paper.1 An attempt was therefore made to prepare curves showing the hardening produced by various concentrations of a chrome alum solution with the addition of varying proportions of acetic acid,
* Communication No. 432, Kodak Research Laboratories (continued from May, 1930).
667