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Basic Chemical Formulae Basic Chemical Formulae The bare necessities of a life in the darkroom Among the plethora of developers, fixers and toners Equipment you need to get started: Typical Metric Units are an essential few, which will persevere through (use in photographic formulae) fashion and commercial profitability. The following 1. an old fashioned chemical balance or a modern is a complete set of basic formulae, which are essential electronic scale, accurate to at least ±0.1 grams 1 kg = 1,000 g for archival processing. We do not recommend to and weighing up to 100 or 200 grams 1 g = 1,000 mg anyone to prepare their own chemistry as a means of 2. plastic syringes of up to 1, 5 and 10 ml to ac- ‘saving money’, but if you have a hard time obtain- curately measure very small liquid volumes 1 l = 1,000 ml ing darkroom supplies in your area, or if you like to 3. a set of graduated cylinders, ranging from 30 1 ml = 20 drops modify proven formulae in order to obtain unique ml to 1 liter for measuring liquids and solids characteristics, the information presented is a good 4. plastic scoops for measuring out chemicals starting point. To see the whole gamut of darkroom 5. one to three plastic beakers, holding 1 and 2 alchemy with all its opportunities and alternatives, get liters each, for mixing working solutions yourself a copy of The Darkroom 6. a small and a large plastic stirring rod to keep Cookbook by Steve Anchell and undissolved chemicals in motion The Film Developing Cookbook 7. plastic funnels for pouring liquids into bottles A Note on Safety by Anchell and Troop, and add 8. a selection of brown glass or plastic bottles to As with all other chemicals, there them to your photographic library. store the solutions and labels to identify them are risks associated with con- These books contain an unri- tact, inhalation and ingestion of valled collection of photographic Initial Shopping List for Basic Chemicals darkroom chemicals. We strongly formulae and easy-to-understand advise that you study the material explanations on how to use them. acetic acid (28%) 500 ml safety data sheet (MSDS) of each Many chemical suppliers do ammonium thiosulfate 2 kg chemical before using it. In gen- not sell directly to the public, borax (sodium tetraborate, decahydrate) 500 g eral, one must always observe the but there are several suppliers of boric acid (granular) 250 g following practices while handling photographic chemicals around citric acid 100 g darkroom chemicals. the world selling directly to pho- hydroquinone 250 g tographers, including Silverprint metol 100 g a. don’t smoke in darkroom in the UK, Artcraft Chemicals, phenidone 25 g b. don’t eat or drink in darkroom Bostick & Sullivan and The potassium bromide 100 g c. wear goggles Photographers Formulary in the potassium ferricyanide 250 g d. wear an apron USA. If you have difficulty find- potassium iodide 50 g e. wear a face mask ing a qualified local source, start potassium permanganate 10 g f. wear rubber or latex gloves by talking to your neighborhood potassium polysulfide (liver of sulfur) 100 g g. ensure good ventilation drugstore or pharmacy. They will silver nitrate 5 g h. never inhale chemical dust be able to either point you into the sodium carbonate (monohydrate) 1 kg i. label chemical bottles clearly right direction or may actually sell sodium hexametaphosphate (Photo Calgon) 100 g you most of what you need. sodium sulfite (anhydrous) 2 kg 502 Way Beyond Monochrome D-76 is a fine-grain, general-purpose film Film Developer (D-76 / ID-11) developer for maximum shadow detail. It was formulated in 1926 by Kodak and still is the distilled water 50°C / 120°F 750 ml standard by which all other developers are metol 2 g judged, because it offers the best compromise sodium sulfite anhydrous 100 g between speed, sharpness and resolution. hydroquinone 5 g Many deviations from this original formula borax decahydrate 2 g have been proposed over the years. A recent cold distilled water to make 1,000 ml suggestion is to omit hydroquinone and raise metol to 2.5 g, creating D-76H, an environ- dilute 1+1 for standard film development mentally friendly and more stable developer. use as one-shot developer for processing consistency D-72 is a neutral-tone paper developer for Neutral Paper Developer (D-72) brilliant highlights and maximum blacks, very similar to Kodak Dektol. Standard dilution for water 50°C / 120°F 750 ml this developer is 1+2. Dilute 1+1 for longer metol 3 g shelf life and slightly higher Dmax, or 1+3 sodium sulfite anhydrous 45 g for warmer tones and softer shadows. It has hydroquinone 12 g excellent keeping properties and an outstand- sodium carbonate monohydrate 80 g ing development capacity. Replace with fresh potassium bromide 2 g developer as soon as factorial development cold water to make 1,000 ml fails to create potential Dmax. Increase potas- sium bromide to up to 4 g for warmer tones, dilute 1+2 for standard paper development similar to Ilford Multigrade or Agfa Neutol NE. very similar to Kodak Dektol ID-78 is a warm-tone paper developer with Warm-Tone Paper Developer (ID-78) a formulation very close to Ilford Warmtone and Agfa Neutol WA. It works well with all water 50°C / 120°F 750 ml modern neutral and warm-tone papers on the sodium sulfite anhydrous 50 g market. Dissolve the phenidone separately in hydroquinone 12 g 50 ml of hot water (>80°C). Standard dilution phenidone 0.5 g for this developer is 1+3, but it can be used as sodium carbonate monohydrate 72 g strong as 1+1 for richer shadows. Replace with potassium bromide 4.5 g fresh developer as soon as factorial develop- cold water to make 1,000 ml ment fails to create potential Dmax. dilute 1+3 for warm-tone paper development very similar to Ilford Warmtone and Agfa Neutol WA SB-7 is an odorless acid stop bath for film Stop Bath (SB-7) and paper processing. It quickly neutralizes the alkaline developer and brings development water 750 ml to a complete stop. Its capacity is approxi- citric acid 15 g mately ten rolls of film or 8x10-inch prints water to make 1,000 ml per liter. Use prior to acid fixers, and precede alkaline fixers with a plain water rinse instead. working solution for paper, dilute 1+1 for film Basic Chemical Formulae 503 Acid Rapid Fixer (RF-1) RF-1 is a non-hardening, acid, rapid fixer for film and paper. The omission of a hardener water 50°C / 120°F 750 ml supports archival washing and makes it easier ammonium thiosulfate 120 g for spotting fluids to be absorbed by the print sodium sulfite anhydrous 12 g emulsion. Dissolve the boric acid separately acetic acid 28% 32 ml in 80 ml of hot water (>80°C) and add last, or boric acid granular 7.5 g substitute with 9 g of sodium carbonate to cre- cold water to make 1,000 ml ate an almost odorless version of this fixer. We recommend using the two-bath fixing method working solution for film and paper for film and fiber-base paper, both at full fixer use two-bath fixing method for film and fiber-base paper strength. The first fixing-bath capacity is ap- with film, use as one-shot fixer for processing consistency proximately ten 8x10-inch prints per liter. Alkaline Rapid Fixer (RF-2) RF-2 is a non-hardening, alkaline, rapid fixer for film and paper, supporting an odorless water 50°C / 120°F 750 ml darkroom environment and significantly re- ammonium thiosulfate 120 g ducing washing times. To conduct an entirely sodium sulfite anhydrous 15 g acid-free process, do not use in combination sodium carbonate monohydrate 0.7 g with an acid stop bath. Instead, follow de- cold water to make 1,000 ml velopment by a 60s wash in plain water, and use the two-bath fixing method for film and working solution for film and paper fiber-base paper at full fixer strength. The use two-bath fixing method for film and fiber-base paper first fixing-bath capacity is approximately ten with film, use as one-shot fixer for processing consistency 8x10-inch prints per liter. Hypo-Clearing Agent (HCA-1) HCA-1 is a washing aid for film and paper, used subsequent to acid fixers. Treat films for water 50°C / 120°F 750 ml 2 and papers for 10 minutes with slight agita- sodium sulfite anhydrous 100 g tion. Used after a preceding water rinse, the sodium hexametaphosphate * 5 g capacity is approximately twenty rolls of film cold water to make 1,000 ml or 8x10-inch prints per liter. With hard water supplies, add sodium hexametaphosphate dilute 1+4 for film or paper (Photo Calgon) to prevent the formation of * add with hard water supplies to prevent calcium scum calcium scum on the emulsion surface. Polysulfide Toner (T-8) T-8 is a direct polysulfide toner for modern papers, similar to Kodak Brown Toner or Agfa water 750 ml Viradon, and can be used at room temperature. potassium polysulfide 7.5 g Wash fiber-base prints for 30 minutes without sodium carbonate monohydrate 2.5 g washing aid prior to toning. Please note that water to make 1,000 ml this toner produces toxic hydrogen sulfide gas, as well as the offensive odor that goes along working solution for direct paper toning with it.
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