Developing black-and-white film

Developing black-and-white film is one of the most satisfying skills in photography, and it can be done at home in a kitchen or bathroom with modest equipment. The process transforms an invisible latent image into a permanent negative in about half an hour. It requires care, consistency and complete darkness for loading, but once mastered, it gives the photographer full control over contrast, grain and tonality. This lesson covers equipment, loading film onto reels, chemistry and mixing, the development sequence, time, temperature and agitation, developer choice, stop bath, fixing and fixer testing, washing and wetting agent, drying and storing negatives, and keeping development records.

Equipment

A basic film developing kit includes:

• A light-tight developing tank with reels: stainless steel tanks with steel reels, or plastic tanks such as Paterson with adjustable plastic reels that accept 35 mm and 120 film. Tanks hold one or more reels, and their lids allow solutions to be poured in and out in daylight once the film is loaded.
• A changing bag or a completely dark room for loading film onto reels.
• An accurate thermometer, ideally checked against a reference.
• Graduated measuring cylinders and jugs, and storage bottles for chemistry, clearly labelled.
• A timer, often a phone app with development times programmed.
• A bottle opener or cassette opener for 35 mm cassettes, and scissors.
• Film clips and a dust-free place to hang film to dry.
• Gloves and eye protection (Lesson 12).

Large format sheet film is developed in trays, in tanks with sheet hangers, in specialized tanks with sheet holders, or in rotary processors.

Loading film onto reels

Loading is the most challenging step for beginners, because it must be done entirely by feel in total darkness. Practise first with a sacrificial roll of film in daylight, then with eyes closed, until loading is quick and confident. For 35 mm, open the cassette with an opener, cut off the tapered leader squarely, feed the film onto the reel (plastic reels ratchet the film in by rotating the two halves; steel reels require clipping the end at the centre and curving the film slightly to wind it into the spiral), place the reel in the tank and close the lid securely before turning on the light. For 120 film, separate the film from its paper backing, noting that the film is taped to the paper at one end, and handle it by the edges, since its larger surface is more easily marked by fingers. Avoid touching the emulsion, kinking the film, which causes crescent-shaped marks, or letting the film overlap on the reel, which prevents development where layers touch.

Chemistry and mixing

The chemicals needed are developer, stop bath (or a water stop), fixer, and optionally a washing aid and a wetting agent. Developers are available as powders to mix into stock solutions, such as Kodak D-76 and Ilford ID-11, which are similar, or as liquid concentrates diluted for each use, such as Kodak HC-110, Ilford Ilfosol 3 and DD-X, and Rodinal-type developers like ADOX Adonal. Dilutions are written as ratios such as 1+9, meaning one part concentrate plus nine parts water, for ten parts in total:

One-shot developers are used once and discarded, giving consistent results. Replenished or reusable developers are used several times with adjustments, which requires record-keeping. Fixer and stop bath are usually reusable up to their capacity. Mix chemistry with water at the recommended temperature, in a well-ventilated space, and label bottles with contents, dilution and date. Store chemistry in full, tightly capped bottles away from heat and light; oxidized developer loses activity and may turn brown.

The development sequence

A standard black-and-white film process runs:

Pour each solution in quickly and start timing as pouring begins; tap the tank firmly on the counter after pouring to dislodge air bubbles that cling to the film and cause small undeveloped spots. Begin pouring out about 10 to 15 seconds before the end of each step, since draining takes time.

Time, temperature and agitation

Development time depends on the film, developer, dilution, temperature and agitation. The standard reference temperature is 20 °C (68 °F). At higher temperatures, development proceeds faster, and times must be shortened; at lower temperatures, it slows. Manufacturers publish time-temperature charts; as a rough guide, many developers change activity by about 8 to 10 % per degree Celsius near 20 °C. Keep all solutions within about one degree of each other, since sudden changes in temperature can cause reticulation, a cracked pattern in the emulsion, though modern films are resistant. A water bath around the tank helps keep temperature stable.

Agitation moves fresh developer to the film surface and removes exhausted developer. A common pattern for inversion tanks is continuous agitation for the first 30 seconds, then four inversions over 10 seconds at the start of each minute. Ilford recommends four inversions in the first 10 seconds of each minute. More agitation increases contrast and density; less agitation, used in stand and semi-stand development, gives compensating effects, enhancing edges and controlling highlights, but risks uneven development and streaks. Consistency is more important than the exact pattern: use the same technique every time, so that results are predictable.

Choosing a developer

Developers affect grain, sharpness, tonality and effective film speed:

• General-purpose developers such as D-76 and ID-11 give a good balance of grain, sharpness and speed and are the benchmark against which others are measured; used at stock strength or diluted 1+1 for slightly sharper results.
• Fine-grain developers produce smaller visible grain, sometimes at a slight cost in speed and sharpness.
• High-acutance developers such as Rodinal-type developers at high dilution emphasize edge sharpness and grain structure, suited to slow films and large formats.
• Speed-enhancing developers such as Ilford Microphen and DD-X give fuller shadow detail when pushing film.
• Compensating and staining developers, such as pyrogallol-based PMK and Pyrocat, produce a stain image that tans the gelatin, controlling highlights; they are more toxic and require extra care.

Consult the manufacturer's data sheets and the Massive Dev Chart for times, and test any new combination with a less important roll.

Stop bath and fixing

An acid stop bath neutralizes the alkaline developer and halts development immediately, protecting the fixer from developer carry-over. Indicator stop baths change colour when exhausted. Some photographers prefer a plain water rinse, which is gentler and avoids acid fumes, particularly with staining developers. The fixer must be used for the recommended time, and fixer capacity must be monitored. A simple clearing test checks fixer strength: place a snip of undeveloped film leader in the fixer and time how long it takes to become clear; the film should be fixed for at least twice the clearing time, and the fixer is exhausted when the clearing time doubles from its fresh value. Under-fixed negatives may show a milky or purplish cast and will deteriorate; if in doubt, re-fix them.

Washing, wetting and drying

Washing removes residual fixer, which otherwise attacks the silver image over time. A running-water wash of about 10 minutes, or 5 minutes after a washing aid, is typical. Ilford's water-saving method fills the tank with water at the same temperature, inverts it five times, drains, refills and inverts ten times, drains, refills and inverts twenty times, and drains, using little water. After washing, a brief bath in a wetting agent, such as Ilford Ilfotol or Kodak Photo-Flo, mixed very dilute, reduces water spots. Hang film by one end with a clip, adding a weighted clip at the bottom to prevent curling, in a dust-free place such as a bathroom after running a shower to settle dust, or a drying cabinet. Avoid squeegeeing, which can scratch the emulsion, or wipe gently with clean fingers or a dedicated wiper if at all. Dry film for several hours until fully dry before cutting.

Storing negatives and keeping records

Cut dry negatives into strips, typically six frames for 35 mm and three or four for 120, and store them in archival sleeves made of polyester, polyethylene or acid-free paper, labelled with date, subject, film and development. Store sleeves in binders or boxes in a cool, dry, dark place. A contact sheet (Lesson 8) filed with each set of negatives makes it easy to find images. Keep a development log recording film, exposure index, developer, dilution, temperature, time, agitation and results; over time, it becomes an invaluable personal reference.

Developing sheet film

Sheet film can be developed in trays, one sheet or a small stack at a time, in total darkness, shuffling sheets continuously from bottom to top for agitation; this is efficient but requires care to avoid scratches from corners. Daylight tanks designed for sheet film hold sheets in slots or holders, allowing development with lights on once loaded. Rotary processors and tubes, such as drum systems, rotate the film in small volumes of developer, giving even development with little chemistry, and are popular for both black-and-white and colour sheet film. Because each sheet can be developed separately, sheet film photographers often mark holders for N, N+1 or N−1 development and process them in groups.

Water quality

Tap water varies in hardness, chlorine content and temperature. For most black-and-white processes, ordinary tap water at the right temperature works well for mixing developer and washing, but very hard water can leave drying marks and some developers are sensitive to minerals. Using distilled or deionized water for mixing stock solutions and for the final rinse with wetting agent avoids these problems. Water filters in the darkroom supply line remove sediment that can lodge in the emulsion during washing.

Developing in a sink or kitchen

Home developing is often done in a kitchen or bathroom. Keep chemistry away from food preparation areas, cover surfaces, and clean thoroughly afterwards. Use dedicated measuring equipment that never touches food. Ventilate the room, wear gloves and eye protection, and store chemistry safely out of reach of children and pets. Plan disposal in advance: used fixer should be collected for silver recovery rather than poured down the drain (Lesson 12).

When things go wrong in the tank

If the lid comes off or light enters during development, close it immediately and finish processing; part of the roll may still be usable. Never open the tank to check progress, since the film is light-sensitive until it has been fixed.