Chemical exhaustion

I recently purchased chemistry for a metol-hydroquinone (ID-20 or GAF125)

developer. I've mixed the metol and sodium sulfite, hydroquinone-everything

seems to progress properly. As soon as I add the sodium carbonate(I've also

experimented with Borax) the solution begins to exhaust itself. Within a couple

of minutes it's brown/black. I've attempted printing with these solutions with

little image being developed. Short of substituting each of the components does

anyone have a suggestion on the best course of action to determine what may be

happening here?

You say it happens when you add the sodium carbonate, is the sodium carbonate a known good batch? I use Leslie's Soda Ash for sodium carbonate, but know my supply is good from the mixes I've done. Are you using distilled water?

As far as I know the source is reputable and the fact that the Borax responded in a similar fashion leads me to believe either I'm doing something wrong or one of the chemicals prior to the carbonate is unstable? The water here has never been a problem in solution.

One of the functions of the sodium sulfite is to act as a preservative and prevent aerial oxidation of the metol and hydroquinone. When I mix developers of this type, dissolving the metol first, the solution becomes a pale yellow due to slight oxidation of the metol by dissolved oxygen in my water. As soon as the sodium sulfite is added, the solution becomes colorless as the sulfite restores the metol to its original state.

 

From your description, it sounds as if something is oxidizing the metol (at least) and the sodium sulfite preservative isn't functioning as it should. If you're certain about the quality of the sodium carbonate being used, you might look to the sodium sulfite, either quantity (unlikely) or quality as being the problem.

I have to agree Wendell. I did the vinegar test of the sodium carbonate-very active response. Any ideas as to a substitution of the sodium sulfite? I do have some ascorbic acid around-I wonder if its' oxygen binding properties would at least let me check the integrity of the formula without the sulfite?

I get my sod carb at the grocery store; Arm & Hammer Washing soda.

 

Ascorbic acid can be a preservative, but it's also a developing agent. If you throw this in with the metol for your ID-20/GAF 125, you'll have an entirely different formula and will have to do testing for times and EI's with the films you want to use.

Sorry, forgot, you're makeing a paper dev. Yes, go ahead and try the A. acid and see what happens.

There is no real substitute for sodium sulfite. It should be placed in the water first, and then the metol and HQ.

 

Whatever order you use, sulfite should be first in the list.

 

Another fact to consider that sodium sulfite goes bad too, and can decompose more quickly than most imagine.

 

Ron Mowrey

Ron, I beg to differ. Metol has a hard time dissolving an alkaline solution. Shouldn't the metol be dossolved first, then the sulfite? I put the sulfite in first once, then the metol. The metol just sat in lumps at the bottom of my beaker and it hadn't gone anywhere 24 hrs. later!

Disolve a pinch of sulfite, then the metol. A pinch is what you hold between your finger and thumb. Too much and metol will not disolve but the pinch stops all oxidation in the beginning. Usually hydroquinone comes next and the the sulphite. But follow the order listed in the formula disolving each completely in turn before adding the next.

 

Make sure you are using sulphite, not sulphate.

I checked my ORWO Rezepte book. In all 27 paper developers

listed which contain Metol among other ingredients, the Metol is

dissolved always first, before the addition of sulfite.

Thanks for all the input. Looks like I'll have to remove or substitute until I find the culprit. My knowledge here is minimal at best and the cause for such a rapid exhaustion eludes me unless a bad batch of sulfite will allow this sort of reaction.

Thanks for all the input. Looks like I'll have to remove or substitute until I find the culprit. My knowledge here is minimal at best and the cause for such a rapid exhaustion eludes me unless a bad batch of sulfite will allow this sort of reaction.

James, it sounds to me as if there's not enough sulphite in your formula. Most formulae call for around 50gms per litre of anhydrous sulphite. That, or the sulphite has "gone off" and oxidised to the photographically useless sodium sulphate.

 

You can also make sodium sulphite by mixing sodium metabisulphite with caustic soda in the right proportions. The right proportions being 19 parts sodium metabisulphite to 8 parts sodium hydroxide, by weight. These need to be mixed in solution, of course, not dry.

 

Sodium metabisulphite should be fairly easily obtainable as it's E223 food preservative, and sold in home-brew shops as a sterilising and preservative powder. Caustic soda is sold as a general household and drain cleaner.

 

Another possibility is that your developer is being contaminated by metal. Any reactive metal will quickly oxidise your developer. The worst common culprits are iron and copper, and if you have cracked enamel dishes, then it's likely that both these metals will be allowed to contact your developer. Copper is especially bad, since it acts as a strong catalyst in combining the developing agent(s) with oxygen. The only cure is to not use any suspect dishes or containers. (BTW, I find that plastic cat-litter trays, unused of course, make cheap and excellent developing dishes.)

 

If all else fails, try using distilled water to make up your developer, and see if things improve.

Oh, one other thing James. You shouldn't use really hot water for making up formulae, because this can break down sodium sulphite or metabisulphite. Water used for making up developers should be no hotter than 40 degrees Celsius (around 100 Farenheit).

Ronald;

 

Thanks for catching my goof. I should have said 'some of' or 'a pinch of' referring to the sulfite. You are of course, correct. You can put it all in before the hydroquinone, as alkali helps dissolve the HQ.

 

Ron Mowrey

All the discussion lead me to research the physical properties of the contents of two similar 2.5kg containers I'd recently purchased. With the honest help of the supplier we determined the labeling was switched between the sodium sulfite the sodium thiosulate!

So while I believed I was using sulfite I was in fact, mixing up a developer with thiosulfate! I expect my next batch may well work as described in the formula.

Thank you all for your input and the helpful hints regarding procedure etc.