DEVELOPING — TWO BATH

This is carried out at 24°C in small tanks. Anywhere between 22°C and 25°C is adequate with minor alteration of times. Both baths are made up on a one shot basis by diluting the stock solution 1:19 with water into two separate vessels (e.g. 15ml of stock solution to 285m1 of water to make 300ml of working solution, or 25ml to 475m1 of water to make 500ml). It is particularly easy to achieve the correct temperature with such high dilution by adding water from a bulk supply premixed in a clean container to the correct temperature. The developer is very tolerant , and a °C either way will make no discernible difference.

It is very important not to allow any of Bath B to get into Bath A in stock or diluted solution form. All films take the same time regardless of make or speed (except very slow technical copying or ortho films being used for continuous tone work for which photographers would have to experiment). It is recommended that 5 minutes in each bath is given for a trial film. Results from this should be well printable, but the time can be fine tuned between approximately 3½ and 6½ minutes in each bath to achieve the kind of negatives that print on your preferred "normal" grade of paper with your enlarging equipment. Obviously you should not process an important film until you have carried out trials of this kind. Stop and fix are normal, but ensure that the acid stop bath is not over strength- an acid processing environment reduces the desirable negative stain effect. Before development, give the film a presoak in water at the correct temperature. If air temperature is greatly different, 2 or 3 changes of presoak can be given, each of about 1 minute, which will help stabilise the tank temperature at that of the solutions. The presoak aids even absorption of the developer to avoid air bells. Pour off the presoak which will also remove any anti halation dyes in 120/220 size films.

Pour in Bath A. Agitate once by inversion, then rap the tank base on a firm surface to dislodge air bells from the film's surface. Continue gentle inversion agitation with a twisting action, and not too violently which could cause frothing, for the first 30 seconds. Again rap the tank base. Agitate thereafter once every 30 seconds until Bath A time is completed. Drain off the developer thoroughly and store if you intend to reuse. Do not use a stop bath, or even a water rinse, at this stage. Pour in Bath B. Agitate once and tap the tank base as above to dislodge air bells, but do not keep agitating in this bath for the first 30 seconds. Agitate gently giving an inversion with a twisting action every 30 seconds thereafter until the required time is complete. Pour off Bath B at the end of its time. Store for reuse -this is important. Please note that it is normal for the Bath B to be a strong brown colour on pouring it from the tank. Indeed, if it is not brown, it is a cause for concern since its necessary oxidisation staining effect will not be acting without such discoloration. Now use stop bath and fix in the usual way. After fixing give a quick clean water rinse to wash away extraneous surface drops and traces of fixer from the film. Now without delay pour back Bath B agitating at 30 second intervals for about 2 minutes. This step is important in activating the chemical reaction causing the stain of the negative image which adds printing density. A slight difference in the colour of Bath B before and after this step should be visible. Pour off Bath B and store if you wish to develop further films in this solution. Wash and dry in the normal way. A minimum 20 minute immersion in the wash also aids the stain formation. This will not be great to the eye, but can be significant in printing terms. The best way to wash is to fill the tank with water at the same temperature as the processing solutions (from the same bulk supply used to mix the solutions), agitate briefly to remove air bells. After about 3 minutes pour off the water completely, refill with fresh water and reagitate. Repeat the cycle at least 6 times. Making the wash slightly alkaline with a tiny amount of fully dissolved sodium carbonate, sodium metaborate, or borax further enhances tanning and staining, and can aid wash efficiency, but is a very minor refinement. Give a penultimate rinse in pure water, which can be de-ionised or distilled, if you use the alkaline solution, or if your mains supply is questionable in any way. After a final rinse in similarly pure water with wetting agent (leave immersed for not less than 30 seconds) the film can be hung to dry, squeegeed or not to choice, in a dust free atmosphere.

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