Single-Powder Developers.

Discussion in 'B&W: Film, Paper, Chemistry' started by Keith Tapscott., Jun 30, 2007.

  1. Keith Tapscott.

    Keith Tapscott. Member

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    I have often been curious of how Kodak make their popular film and paper developers such as D-76, Dektol etc, as single powder compounds.
    I found a patent for this (U.S. Patent# 2,893,865) describing a method for stabilizing the components.
    I'm wondering if this is the same method that Kodak uses?

    http://www.google.com/patents
     
  2. Keith Tapscott.

    Keith Tapscott. Member

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    Boric anhydride and other acids.

    In these patents, Boric anhydride (Boric Oxide) is often cited as one of the components in stabilising single powder developers, this is Boric acid with less water, so makes sense as to prevent caking. This would have the effect of lowering the pH. Is the use of Lithium hydroxide which is also mentioned in some of the patents, there to boost the pH back to the desired value?:confused:

    http://www.google.com/patents?q=Single+Powder+Developers&btnG=Search+Patents