[pure-silver] Re: New Dektol, dark brown

  • From: `Richard Knoppow <dickburk@xxxxxxxxxxxxx>
  • To: pure-silver@xxxxxxxxxxxxx
  • Date: Sat, 27 Mar 2021 20:40:48 -0700

   I mentioned using a liquid concentrate paper developer but could not remember the name. It clicked in. Agfa Neutol Plus. This is (probably) a Phenidone and isoascorbic acid developer. It had some good properties but I thought it looked flat somehow.
   I have no idea what is in LPD, it has been suggested it is Phenidone and hydroquinone. If so it must be similar to Ilford Bromophen. If its performance is much different then it can't be the same stuff.
   I would note that the performance of conventional M-Q developers can vary quite a lot with the balance of M and Q and with the pH. For instance, Kodak has three published formulas, D-72, probably the same as Dektol, D-52, probably the same as Selectol, and D-73 an active developer described as a Blue-Black developer. The difference in the formulas for D-72 and D-52 are quite obvious but the difference between D-73 and D-72 are much less and in the direction of more hydroquinon, less metol and more carbonate. I have never tried it. I will also point out again that the recommended strength of dilution of developers varies. In its modern instructions for D-72 or Dektol Kodak recommends diluting it 1:2 but in the 1940s instructions the dilution varied from 1:1 to 1:4 depending on the paper to be processed. My own experience is that 1:1 gives somewhat better contrast and Dmax than the recommended 1:2. Agfa/Ansco recommended 1:1 for 130 for all papers. I suggest that those who find Dektol does not give them good Dmax or don't like the curve shape try using a stronger dilution to see if it cures the problems. I will post the formula for D-73 later for those who have the materials and like cooking their own. Same ingredients as D-72.
   FWIW, the MSDS for Neutol Plus does not list the developing ingredients, which are listed as non-toxic. It shows the use of potassium salts. Not surprising since it is a liquid concentrate and in general potassium salts are more soluble than sodium.


--
Richard Knoppow
dickburk@xxxxxxxxxxxxx
WB6KBL

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