Mixing order with phenidone

Discussion in 'B&W: Film, Paper, Chemistry' started by MSchuler, Jan 15, 2008.

  1. MSchuler

    MSchuler Subscriber

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    Yesterday, I mixed up a batch of E-72 as an alternative to the D-72 that I normally use for B&W paper. This was the first phenidone-based paper developer I've mixed and I added components in the order that the Darkroom Cookbook identifies (phenidone, sodium sulfite, ascorbic acid, etc.), adding a "pinch" of sulfite first as done for MQ developers. Although I was using distilled, boiled (deoxygenated) water, there was a faint but noticable darkening from oxydized developer, I assume, when I added the phenidone, which disappeared immediately upon adding the ascorbic acid.

    My first question is: is this normal for phenidone or could there be some other problem? I'm headed into the darkroom to test the developer now, but thought I'd check to see if anyone has any input.
     
  2. Tom Hoskinson

    Tom Hoskinson Member

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    Phenidone will oxidize quickly when dissolved in water.

    Disolved in propylene glycol, triethanolamine (or a combination of the two) phenidone lasts for years. Instant Mytol is an example of a recipe that includes both phenidone and ascorbic acid - Instant Mytol's intended use is film development - but at low dilutions it also works as a print developer. You can add Potassium Bromide and/or Benzotriazole to change the image tone.

    http://www.apug.org/forums/forum223/33880-instant-mytol.html