Re: LC-1 developer question
From: david drake <email@example.com>
Subject: Re: LC-1 developer question
Date: Thu, 27 Mar 2008 13:41:17 -0400
> So, do I need to be using double the amount of sodium
> sulphite or would the normal amount of 60 grams work?
First of all, reducing sulfite may increase the solubility of
Metol, but it may not be enough to solve your problem.
All these will have to be determined experimentally. The
amount of sodium sulfite has influence on the development, and
it depends heavily on the type of the emulsion being used.
The term "lith film" doesn't really describe much, since the
term "lith" is commonly abused to mean high contrast emulsions
for printing films in general, and there are a very wide range
of such emulsions. Generally speaking, modern printing
emulsions are monodisperse cubic AgBr emulsions of 0.05 to 0.2
microns edge length, sulfur sensitized. Most modern ones
probably make mostly surface image, and don't really require
much sulfite to develop properly. But depending on the nature
of latent image centers (determined largely by chemical
sensitization and crystalline defects introduced to the
crystals), varying the amount of sulfite may affect the
sensitometric curves of the overall system.
More immediate effects, however, is that the pH of the
developer will likely change if you change the sulfite content
without adjusting the pH, and this will have a direct impact
on the developer activity and sensitometric curves with
whatever emulsion you use.
In a low pH Metol developer, doubling the Metol concentration
does not double the rate of development. If your main
complaint is long development time, I suggest you try raising
the processing temperature, raising pH slightly, or
"Make something religious and people don't have to deal with it, they
can say it's irrelevant." (Bob Dylan, Biograph booklet, 1985)