[pure-silver] Re: Toner for chocolate brown tone

Up to 240 grams per liter? Isn't that kind of a lot?
Ryuji Suzuki found a patent issued to Ira Current who was Ansco/Agfa's toner expert. The patent is for "Cold Sepia Tones". In it he shows that a very large amount of Potassium Bromide in the developer will cause the toned image to shift from red to blue. This is about the opposite of the conventional wisdom but he shows spectrograms of the reflected light to prove it. The patent is: 
USP 2,607,686
Current gives two developer formulas. One is special but the other is Agfa/Ansco 103, a cold tone developer originally for contact papers. It is similar to Kodak formula D-73, slightly more active than Dektol/D-72. One could get about the equivalent by adding about 10 grams/liter of Sodium Carbonate, monohydrated to Dektol/D-72 and then adding the bromide. Current specifies adding Potassium Bromide, 60 to 240 grams per liter to the stock solution. The normal developer has about 2 grams/liter of Kbr. The developer stock was diluted normally, that is one part stock to 2 parts water. Prints were developed up to 10 minutes. Current states he toned in both a Liver of Sulphur toner (Kodak Brown Toner) and in a bleach and redevelop ("indirect") sepia toner. The color of the toned image varies with the amount of Bromide added to the developer. 
    I think  this is at least worth a try.
You can get any United States patent from the Patent office site at http://www.uspto.gov You will need a plug-in to see the FAX tiff files. The best is Alternatiff, which is free ware and available in two forms, one for Internet Explorer and the other for Firefox and other browsers not using Active-X. You can also find patents on the Google Patent site at http://www.google.com/patents 

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Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx

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