Re: LC-1 developer question
From: david drake <daviddrakephoto@sympatico.ca> 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 combination thereof. -- 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)
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