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.
680
LEVENSON
December
Effect of Colloidal Silver on Autoxidation Rates
No definite change in the rate of oxidation of developing agents in the runs on the five systems could be associated with the addition of colloidal silver.
Volmer10 observed that the addition of colloidal silver accelerated the darkening of alkaline developing-agent solutions on aeration. Weissberger and Thomas11 examined the effect of colloidal silver on the rate of absorption of oxygen by sulfite-free solutions of developing agents. Their experiments on Elon and hydroquinone, made at rather low pH. levels (between pH. 7 and 8), showed that colloidal silver slightly accelerated the absorption of oxygen by hydroquinone.
Fig. 9 — Course of autoxidation when 1-liter samples of the positive developer at pH 10.5 were aerated together, one containing colloidal silver.
Colloidal silver had almost no effect on the initial rate of absorption by Elon, but the partially oxidized Elon solution absorbed oxygen much more slowly in its presence. An experiment on p-aminophenol at pR 9.2, a level closer to those used in the present work, showed a marked increase in the initial autoxidation rate when colloidal silver was added, though, as in the case of Elon, the partially oxidized solution absorbed oxygen much more slowly in the presence of the silver.
To check the influence of colloidal silver on the rate of autoxidation of developers more precisely than it was possible to do on the pilot systems, experiments were made on 1-liter samples of the positive developer (pR 10.5). Compressed air, at a constant rate of flow, was moistened and then bubbled through two 1-liter cylinders arranged in tandem, separated by an empty flask which acted as a spray trap.