Mix your own chemicals - traditional darkroom ideas

You don't have to buy ready made film processing solutions. For the more adventurous or budget conscious all the necessary ingredients for developers and fixers can be bought separately and mixed when required.

Here's how:
Formulas for most common and uncommon developers, fixers, toners and oddball processes can be found either in books on darkroom or on the web. Providing you have suitable scales to accurately weigh out powder ingredients and a small measuring cylinder for fluids along with a larger measure to mix in and a thermometer you can buy and mix your own solutions following our simple instructions.

Before we begin it is essential that you follow these warnings

Many chemicals and solutions used in photographic formulas are harmful if they come in contact with skin - just like any household cleaning liquids and disinfectants. To be on the safe side treat all with equal respect.

• Wear eye protection while mixing solutions and wear rubber gloves.
• Do not allow contact with skin.
• Chemical combinations can produce harmful vapours so ensure you work in a very well ventilated room.
• Keep all chemicals in labelled bottles, preferably with childproof caps and definitely out of reach of children or pets.
• Use a funnel to pour mixtures into a bottle
• Do not store solutions in high temperatures or sunlight.
• Do not pour chemicals down the drain unless they are heavily diluted with water  check with your local environment office what the best procedure is to dispose of chemicals.
• Always add powders or liquids to the water to avoid powders being lumpy and liquids spitting.
• Wipe up spills immediately to avoid staining or erosion
• Stick with recognised formulas and do not try to create your own formulas unless you know exactly what you are doing.

Okay so you have the health warnings, now let's look at making one of the most popular developers Kodak D-76. This developer, like Ilford's ID-11, allows full emulsion speed and delivers excellent shadow detail, normal contrast, and produces fine grain from continuous-tone black & white films.

Heat the water up to 50 C (125 F) and pour 750 millilitres into a suitable container. Carefully add each of the ingredients in the order that they are listed above and stir thoroughly at each stage to ensure the chemicals are mixed. Introduce powder slowly as you stir to ensure it mixes well. When the Borax has been added and stirred add water to make the solution up to 1 litre.

This is a stock solution that can then be diluted one part water to one part D-76 to give the working developer. When diluted you obtain greater sharpness, but with a slight increase in grain.
The recommended temperature for this is 20C and all times quoted below are in minutes and based on the developer being used at this temperature.

Here are a couple more formulas to make complimentary Stop Bath and Fixer

Stop Bath
The ingredients are as follows:

Water 1 litre
28% Acetic Acid 48 millilitres

Heat the water up to 32C (90F) and carefully add the acetic acid. Acetic acid is volatile so it must be handled with extreme caution. Do not inhale and do not add the water to the acetic acid. This can cause the acetic acid to boil and will spit out in all directions.
Use undiluted, for about 30 seconds, and discard the used solution after processing.

General purpose fixer

Heat the water to 50 C (125 F) then pour 600 millilitres into a suitable container. Carefully add each of the ingredients in the order that they are listed above and stir thoroughly at each stage to ensure the chemicals are mixed. Introduce powder slowly as you stir to ensure it mixes well. When the Potassium Alum has been added and stirred add cold water to make the solution up to 1 litre.

Use the fixer neat (not diluted) at 20C (68F). Fix for up to 15 minutes and discard after use. You can check that the film is fixed by holding it up to light. If there are any signs of cloudiness continue to fix until this has cleared.

Raw chemicals can be purchase from any good specialist darkroom dealer.