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

Re: LC-1 developer question

From: Richard Knoppow <dickburk@ix.netcom.com>
Subject: Re: LC-1 developer question
Date: Thu, 27 Mar 2008 23:20:21 -0700

> I still suggest warming the solution to see if it will go
> back into solution. I have also heard that adding about an
> ounce of rubbing alcohol per liter will help it go into
> solution, worth a try because if the developer is already no
> good it can't hurt.

I think warming the solution and continuous agitation is most
useful. A small amount of alcohol is probably not going to
help much.

When you try to make a concentrated developer stock with high
sulfite content (30% or higher), this is a very common
problem. The organics (Metol, Dimezone, antifoggants,
ethanolamines, etc.) do not like to mix with water phase
containing a lot of sulfite or other inorganic electrolytes.

Even if you add mild solvents, such as 2-propanol, glycerol,
glycols, and so on, it simply happens that the organics
dissolve mostly in the organic solvent phase, and polar
compounds dissolve in the water phase; these phases
separate. If you mix plain water and any of these organic
solvents, they are completely miscible and so you may be
surprised to hear this, but when you increase the salt
content, they become more like oil and water.

When this happens, you can add a dispersant or a surfactant to
make an emulsion, but they'll eventually separate again. I've
also tried to make this type of emulsion and then add emulsion
stabilizers, soluble polymers, etc. This approach does not
work, unless the user shakes the bottle before use. I don't
want to print "Shake before use" on my bottles, and I always
specify opaque bottle material, so you won't even see if
shaking is enough.

Among many organic solvents I tested, you won't be surprised
to hear this: effective solvents were bad for humans,
environment, or both.

For example, some Sprint developers use dimethylformamide
(DMF), which is suspected to be a carcinogen, and also
suspected to cause birth defects. Well, DMF is a very common
solvent, useful and also easy to use in many situations, and
made by many manufacturers including BASF and E. I. du Pont de
Nemours, but it may not be as bad as some reports
say. However, I decided to formulate my developers without
such solvents.

I have looked into all sorts of possibilities to make
Silvergrain developers (including not-yet-released ones) as
concentrated as possible. Other than selling powder chemicals,
increasing the concentration is one major way to reduce the
transportation load, and I'm serious about this. But I found
that no additional organic solvent could improve the developer
concentration without adding problems.

Ryuji Suzuki
"Make something religious and people don't have to deal with it, they
can say it's irrelevant." (Bob Dylan, Biograph booklet, 1985)