Re: LC-1 developer question
Without doing a wet lab work I can't really tell you how much but I'd cut the portion of Part B. The more B is added, the more acidic the developer will become. I've not done research on Fujifilm HG HSA film so I don't know the exact nature of this emulsion. First thing you need to know is whether the emulsion is chloride based or bromide based. Optimal developing conditions vary between them, especially in terms of sulfite concentration. Usually you can tell that by looking at the processing chemicals for the particular exposure/film/processing system. Chloride emulsions allow much faster processing time and higher processing capacity per chemical change. Laser scanner emulsions are particularly designed for high contrast, even if the same film is also used for continuous tone images, to reduce the effects of light scattering and smearing. There are a number of different generations of technologies that went into this line of emulsions, and it's hard to predict which type a particular product is without doing a specific research. -- 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) From: david drake <daviddrakephoto@sympatico.ca> Subject: Re: LC-1 developer question Date: Thu, 27 Mar 2008 17:22:49 -0400 > Ryuji, what would you suggest adding to raise pH slightly? I have been processing at 75 degrees, but will try higher. > The 'lith' film I have been using recently is a Fuji scanner film HG HSA. I also use APHS but haven't tried with LC-1. > > LC-1 developer formula: > part A (1litre solution) > 3 grams metol > 3 grams hydroquinone > 60 grams sodium sulfate > part B (1 litre solution) > 10 grams sodium bisulfate > > Thanks very much for your help. > > david > > > On 27-Mar-08, at 3:06 PM, Ryuji Suzuki wrote: > > > 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) > > david drake photography > www.daviddrakephotography.com > > > >
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