Wednesday, February 2, 2011


Ascorbate developers has to do with mixing your own stuff.

A lot of recipes are circulating on the Net, some of which are really confusing, since they obviously are written down in haste by people with absolutely no clue about chemistry.

That might seem puzzling since what we now call analogoue photography in truth is about chemistry and might as well be called chemical photography.

If we try to convey information results and knowledge to anyone across the wast internet, we better make dead sure that information is clear and concise and not to be misunderstood at the other end of the line.

Therefore I always prefer to present my recipes and data in the metric system of measurement, AKA as scientific measurements.

When mixing chemicals, litres, grams and millilitres and milligrams are the measures, as well as knowledge on how to calculate percentile solutions.

When I present data, I will always give measures in grams and millilitres.

However, since american friends are born with 12 fingers, I will also give data in the nearly incomprehensible US way of measuring stuff like this : US fl oz, teaspoons and tablespoons, where appropiate. I was considering including grains as a measure of weight as well, but found out few outside of home reloading groups use that, these days.

I have done some research into US measures, trying to dechipher some US recipes, and will give you what I've found so far.

I try to make things simple and have standardized on the recipes given by Reinhold in his blog. But as I like to experiment when I have time, I'm also trying out US recipes, translating their measures to grams and millilitres in the process.

Standard recipe from Reinhold, Coffenol CCH :

Water 750 ml
Washing Soda 54 gram
Ascorbic Acid (E300) 16 gram
Instant coffee (Brazero) 40 gram
Potassium bromide (KBr) 0.75 gram

Top up water to 1000 ml (1 litre)

This standard recipe will work with most films B/W, Color negative (C41), Color slides (Ekta and Kodachrome)

A good starting point for development time is 16 minututes @ 20 centigrade.

Since caffenol don't last well in storage, its a good idea to mix what you need at the time. Since most developing tanks ony uses a fraction of a litre per 35mm film, its a good idea to mix just what you need.

My JOBO tank needs ca 250 ml per film, my Paterson Syst 4 tank needs 290 ml per film.

I find that ca 320 ml (11 US fl. oz) is a good starting point and measures out accordingly.

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