Metol, Phenidone & Hydroquinone.
Most B&W developers contain Hydroquinone with either Metol or Phenidone or a Phenidone derivative. Both Metol and Phenidone are super-additive with Hydroquinone, so why add both of them in the same developer formula?
Here is an example of a developer which contains all three of those constituents. http://www.tetenal.com/sidaopener_uk...auk/100152.pdf |
Metol, Phenidone & Hydroquinone.
"Keith Tapscott." wrote in message ... Most B&W developers contain Hydroquinone with either Metol or Phenidone or a Phenidone derivative. Both Metol and Phenidone are super-additive with Hydroquinone, so why add both of them in the same developer formula? Here is an example of a developer which contains all three of those constituents. http://www.tetenal.com/sidaopener_uk...auk/100152.pdf -- Keith Tapscott. I've wondered the same thing. There are a number of developer formulas that have more than two developing agents in them, sometimes puzzeling combinations. My chemistry is not good enough to know why. -- -- Richard Knoppow Los Angeles, CA, USA |
Metol, Phenidone & Hydroquinone.
"Keith Tapscott." wrote in message ... Most B&W developers contain Hydroquinone with either Metol or Phenidone or a Phenidone derivative. Both Metol and Phenidone are super-additive with Hydroquinone, so why add both of them in the same developer formula? Here is an example of a developer which contains all three of those constituents. http://www.tetenal.com/sidaopener_uk...auk/100152.pdf -- Keith Tapscott. Its interesting also that it contains both potassium carbonate and sodum metaborate. There are some developers, notably Kodak D-7, a pyro-metol developer, where the metol serves mainly as a preservative for the pyro. Metol is a prodigeous oxygen absorber. Its also curious that its the only ingredient in the MSDS which has detailed hazards although hydroquinone is usually considered more hazardous than metol. -- -- Richard Knoppow Los Angeles, CA, USA |
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It may or may not contain a restrainer or perhaps it contains more than one restrainer. |
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