Sunday, March 27, 2011

Sodium Ascorbate, SALS 12

I have recently added Sodium ascorbate powder to my arsenal.

Sodium ascorbate is what is said to be the net result of the chemical reaction that takes place when we mix Di-Sodium carbonate with vitamin C  (Na2 CO3 + ascorbic acid).
It is said that sodium ascorbate is the (most) active developing agent in all the coffenol C recipes.

Since I have that on hand, and haven't really tried it, save for an experiment that failed (yes I will write up my failures also, not afraid of that, so that others can learn from what I have failed), I decided it was time to try this out.

But what recipe? I haven't seen much other than discouragement, and wrnings that this does not work. I was told it was a waste of time, on Sites that waste endless amounts of time discussing coffe......

I want something simple, of ingredients I have in the house, save for the sodium ascorbate thast was ordered 100% pure powder from the pharmacy, where others get their life-saving medicines.

So... I have washing soda (Na2CO3), i have lye, in the form of little pearls (NaOH), the first is a medium base, with a pH around 12 in a 1M solution, the other is a very strong base, with a pH around 14 in a 1M solution, thats a difference of 1:100.....

Na2CO3  molecular weight ca 106g;  1M solution = 106 g/litre
NaOH  molecular weight ca 40g;        1M solution = 40 g/litre

I want a little weaker mix to take down pH and hence activity.

A mixture of
NaOH        0.01 M
Na2CO3    0.05 M  calculates out to a pH of ca 12.0  that is a good, robust pH, which should faciliate dev. agent activity.

So my tenative, experimental recipe will be :

SALS 12 :

Water 500ml
Lye pearls (NaOH)             : 0.4 gram
Washing soda (Na2CO3)   : 5.3 gram
Potassium bromide KBr    : 15ml   10% solution
Sodium ascorbate powder  : 15 gram
Water to 1000ml

* note I added 1,5 gram KBr to the recipe in order to avoid chem. fogging.

I have 2 films ready, exposed identically in two Canon IX Lite bodies at the same time under identical light. I develop my C41 APS films myself in an adapted tank, it is fun and it frees me from the 1-hour lab, that has been detoriating over the last few years....

I intend to do both in this developer, since that puts this experiment in comparison with my other work with Cofenol C-M and C-L and since I have two identical films, it should allow me to get two datapoints on activity and development times.

Initially I view this proposed developer as a developer that will keep in a closed bottle, almost like D-76, and that needs to have the development times adjusted as more and more films are developed, just like D-76.

My starting point will be 16 minutes @ 20 degree centigrade, standard agitation regime.

Developer now mixed with no problems, ready to start experiment.
Film is Kodak Advantix Ultra, APS C41 film, 25 exp.

First result : very thin, barely scanable negatives.  I gave it extra agitation also, still just a few barely useable negatives.  Need to find my thinking cap.....

Pictures  when the film dries by tomorrow the soonest.

Descision: I just will up the pH in this mix, as it is I need to at least increase dev. time 4-fold, and maybe go for 60min to 70 min time and stand development.


Water 500ml
Lye pearls (NaOH)             : 4.0 gram
Washing soda (Na2CO3)   : 10.6 gram
Potassium bromide KBr    : 15ml   10% solution
Sodium ascorbate powder  : 15 gram
Water to 1000ml

pH is now around 13.0 - up a full pH unit.

To make this easy I just added 3.6 gram NaOH and another 5.3 gram to the developer and will try the nest film tomorrow with a dev. time of 20 minutes @ 20 C, extra agitation.

And it works!

I developed a 25 exp roll of Agfa APS Star 200 today in the revised SALS13 brew.
Did an educated guess (guesstimate) on the development time and was very tense when I did brak open the tank!

Development time 32 minutes plus 1 minute extra for the roll developed in the brew yesterday.  Yesterday the brew turned a little yellow (slight yellow thinge in the fresh mixed brew) after I fortificated the mix with extra lye and soda, elevating the pH to 13 or thereabouts, the mixture immediately got a deeper color.
Today after the second roll, I immediately spotted that *something had happened* inside the tank, the brew that got poured back in the storage bottle was definiteli getting a light brown color.

After normal fix in a rapidfixer, and normal wash (8 changes of water, plus two extra with two drops of detergent, should reach nearly archival quality) I got the film out, now hanging to dry. 

The base color on Agfa is a little deeper yellow-brown than Kodak, The negatives are strong and musty.  I'd say this was a complete success.

Also one could get way with about 3,5 gram per litre of Lye pearls alone, plus sodium ascorbate, with just a gram of sodium bromide, one cannot find a simpler developer.

If one changes sodium bromde with citric acid for fog control, the ingredients are not hard to find.

I will publish scans from both films in a separate instalment, so far I'm satisfied and will now go on using this litre until its exhausted, adjusting development times as I go along, have to run to make some exposures, trying out 1+ and 1- exposures to see the latitude.



  1. Ascorbate does work as a developer but in my experience not a very good one. pH does need to be high to activate it but the results were high fog. In my experiments I found ascorbate most useful as a superadditive pair with other developing agents (e.g. Phenidone, Metol, Catechol, p-Aminophenol, etc.) at a pH that's low enough not to activate the ascorbate itself. I'm curious to see your results.

  2. I will heed your advice and include KBr as well I always keep a bottle of 10% KBr here. Lasts for ever!