Lith developer formulation question
I've been trying to develop a decent lith developer with mixed success. I've figured out the right balance between hydroquinone, sod. sulfite, and KBr for me. I'm using saturated Pot. carbonate as the alkali. I'm basically not happy with the developer life both on the shelf and in the tray. With help, I figured out I want the Part A to have a pH of 4.....what is the best acid to achieve that? Regarding the tray life, is there anything other than sodium sulfite that would serve as an anti-oxidant? Thought about ascorbic acid, but it seems that adding a developing agent would be a bad idea.
Anyway any insight from the chemists out there would be greatly appreciated.
Mark, have you ever tried what is known as Ilford ID13/Ansco 70 formula? Just curious, as I wanted to try mixing my own as well and some people have had success.
ID13 isn't really a lith developer it's just a high contrast developer, Kodak 85b is a lith developer though and works well.
You might ask what the difference is - Lith developers have a property called "Infectious development".
It's amazing how simple a lith developer can be. My problem with the more simple formula (hydroquinone, sodium sulfite, potassium bromide & alkali) was that they had no tray life. Sometimes 5 8x10 prints was all I would be able to pull from a litre or two. Considering the first one was usually ordinary, that wasn't so great. If you seperate the alkali (like in ID-13), you get a pretty stable developer in terms of shelf life.
Boric acid is used in lith developer formula. It might be a good choice to achieve the ph you're after. It also has benefit of acting as a ph buffer in small amounts; or so a chemist told me. There's mention of it in this thread:
I'm no chemist, for the record!
Insofar as ID-13 (and the other similar formula), it works. I usually found diluting it in the ballpark of 1:1:9 was ok for lith printing. If you use a stronger concentration, the sodium sulfite levels are too high and you won't get infectious developer. Colour wise, and dmax wise, it's nothing special. You can definitely lith print with it, but when you compare it to a commerical product like LD20 or Moersch... well... it's rubbish.
Thanks, Ian, yes, I am aware of that. Some people have had success with certain papers (notably Slavich, which is hard to tame in most commercially available developers).
Originally Posted by Ian Grant
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I talked with a chemist friend of mine and he recommended acetic acid to pull down the Part A pH. I had tried sulfuric with poor results since sulfuric is also a nice oxidizer (didn't know that). I tried boric acid figuring that I'd get some buffering out of it too, but I added quite a bit and the pH didn't move much. I'm not that sure I really need a buffering agent anyway. I'm sure I can get good enough shelf life. Tray life is really the challenge. I know it is possible because the Rollei and Moersch have much better tray life. The same chemist friend suggested either more hydroquinone or maybe trying ascorbic acid. Ascorbic acid is a weak developing agent, but it may be OK in small amounts. Worth an experiment or two.
Regarding Ansco 70, it looks like the main difference between it and what I am doing is that it uses potassium metabisulfite rather than sodium sulfite. Is potassium metabisulfite a better anti-oxidant? The other differences are more KBr and a different alkali.
I'm a good mechanical engineer, an OK photographer and a lousy chemist!
Last edited by Mark Fisher; 05-09-2013 at 12:47 PM. Click to view previous post history.