U of S | Mailing List Archive | alt-photo-process-l | Re: LC-1 developer question

Re: LC-1 developer question

  • To: alt-photo-process-l@usask.ca
  • Subject: Re: LC-1 developer question
  • From: Richard Knoppow <dickburk@ix.netcom.com>
  • Date: Sat, 29 Mar 2008 23:29:14 -0700 (GMT-07:00)
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-----Original Message-----
>From: Ryuji Suzuki <rs@silvergrain.org>
>Sent: Mar 29, 2008 10:39 PM
>To: alt-photo-process-l@usask.ca
>Subject: Re: LC-1 developer question
>There are a lot of things that don't really matter in real
>life and if you look at old literature you'll find a lot of
>Both Metol and sulfite can react with molecular oxygen
>dissolved in water, but in reality, the rate of that oxidation
>reaction is rather slow. Compounds that react with oxygen fast
>are not very useful as a developer preservative.
>It doesn't really make much difference regardless of which
>gets dissolved first, since a pinch of sulfite is not

    To clarify, I assume you mean in terms of the de-oxgenating the water since dissolving the sulfite first makes dissolving the Metol difficult. 

>instantly removing dissolved oxygen. If absolutely minimal
>oxidation of Metol is required (such as in research
>developers), it is probably more important to deaerate the
>water and dissolve all ingredients as quickly as
>possible. However, if deaeration is necessity for a particular
>developer, I would have to say that the developer is poorly
>formulated and not good enough for practice.
>If you dissolve Metol separately in an alkaline solution and
>combine with high salt content, it may be easier to make all
>the solids go into the solution. However, it is difficult to
>say whether the dissolved state is stable. Even if the
>concentration in the bulk solution exceeds the solubility
>limit, the solution may be in the supersaturation
>state. However, if there are some seed crystals, or some
>debries, or even some rough surface on the container, the
>crystals may grow on it fast (thus supersaturation decreases)
>and only then you realize the problem. If the formula is well
>made and well tested, none of these needs be worried on the
>user side.
>Ryuji Suzuki

     A related question: Do you have any idea of what Kodak does to make it possible to dissolve combined powder chemicals like D-76 and Dektol?  Long ago some developers which are now a single powder came in two parts. 

Richard Knoppow
Los Angeles, CA, USA