Black and White Photography

Some developers work quickly, while others take much longer. Developing
time is determined by several factors. These include the type of film and film
developer, developer dilution, and solution temperature. All are critical. Most
packages of film and developer include a time-temperature chart, which takes
the above factors into consideration and recommends a developing time. But
not all films or developers include such charts; the ones that do list only a few
film and developer choices. Many school and other gang darkrooms have timetemperature
charts posted, but if you can’t find one for the type of film and
developer you use, you can get it from the manufacturer’s Web site.
Note that developing times are important, but minor variations are not fatal.
If the recommended developing time is 10 minutes and you develop instead for
11 minutes, you will still get a printable negative. In fact, it’s best to think of
times from a time-temperature chart as recommendations; they are not set in
stone. Still, you shouldn’t vary from recommended times unless you have a
specific reason to do so.
Stop bath. The developer continues developing film until neutralized by a stop
bath, which usually consists of a very mild solution of acetic acid. You can use
a plain water rinse to end the developing action, but an acid stop bath is more
effective and helps preserve the next solution, the fixer, which is far more critical
to the developing process (and more expensive) than the stop bath.
Stop bath comes packaged as a liquid and is available in several forms. It’s
easier to use a prepared stock solution, consisting of acetic acid. All you have
to do is mix this solution with water for use. With one popular brand you mix
1 part prepared stop to 9 parts water; for example, mix 3 oz of stop to 27 oz of
water to yield 30 oz of working solution, or mix 100 ml of stop to 900 ml of
water to yield 1000 ml (1 liter) of working solution.
Many prepared brands, sometimes called indicator stop baths, contain a dye
to indicate the freshness of the stop bath. For example, the color of a fresh solution
may be yellow, but turn purplish-blue as it becomes depleted, at which
point it’s time to mix a fresh batch.
Be very careful when handling any concentrated form of stop bath. When
diluting an acid, add the acid to the water, to avoid spattering; never add water
to an acid. The fumes may be strong and the solution caustic. Use rubber gloves
when mixing, wear an apron or other protective clothing, and avoid breathing
fumes directly. Don’t use glass bottles or containers to store stop bath; use plastic
instead to avoid breakage.
You can store stock and working solutions of acetic acid for a very long
time—months and even years. The capacity of a working solution varies from
brand to brand, but generally 1 quart or liter of working solution should be
used for no more than 20 rolls of 36-exposure 35mm film (or 40 rolls of 24-
exposure 35mm film) or 20 rolls of 120 medium-format film.

Fixer. After treatment in the developer and stop bath, all silver particles that
were exposed to light in camera have darkened to form the image. However,
the film still contains silver particles that were not exposed to light in camera.
Fixer, sometimes called hypo, is the chemical that removes this unexposed (and
thus undeveloped) silver, allowing the film to be viewed safely in the light. Left
unfixed, unexposed areas will eventually darken with exposure to light and
ruin the results.
Fixers come in powder and liquid form. Powdered fixers are usually less expensive
and slower acting than liquid fixers. After you dilute the powder with
the specified amount of water, you use the same mixture for fixing either film
or prints. To avoid inhaling any concentrated powders that may become airborne,
slowly add the fixer to water while gently stirring.
Many liquid fixers are rapid fixers: They work about twice as fast as powdered
fixers. Moreover, they are safer to handle, as you don’t have to worry
about airborne powders, and more convenient to use. With a powdered fixer,
you generally mix the entire package and store it in a bottle between uses.
Using liquid fixer allows you to make a small batch of solution as you need it.
However, make sure you read the package directions carefully. Liquid fixers
often require different dilutions, one for film and one for paper.
With one particular brand of liquid fixer, you mix film fixer in a ratio of
2:8—2 parts fixer concentrate to 8 parts water; for example, mix 6 oz of
concentrate to 24 oz of water to yield 30 oz of working solution, or mix 200
ml of concentrate to 800 ml of water to yield 1000 ml (1 liter) of working
solution.
Working solutions of fixer can last a long time when properly stored—
several weeks when used and several months when unused. Check the package
instructions or manufacturer’s Web site for recommendations.
Take care not to overuse the fixer, as weakened or depleted solutions may not
work effectively. If in doubt about a fixer’s freshness, use a fixer check (also
called hypo check). Squeeze just a few drops of fixer check solution into a small
container of used fixer. If a white, cloudy precipitate forms, the fixer is depleted
and should be discarded; if no precipitate forms, the fixer is still fresh.
Another way to judge fixer strength is to use a piece of unexposed, unprocessed
film. If you soak the piece in the used fixer, the film should completely
clear in less than one minute. If it doesn’t, mix and use fresh fixer.
Hardener is a fixer additive that toughens the film emulsion, making it more
resistant to scratching and minor damage from handling. It is not absolutely
required when fixing film, but it is highly recommended. Hardener usually
comes premixed with powdered fixers or in a separate bottle to add to most
liquid fixers. Some brands of liquid fixers have hardener built in.Fixer remover. After treatment in fixer, film is fully processed; you can view it
safely in the light. However, any remaining byproducts of the fixing process can
lead to image deterioration, so you must always thoroughly wash the film.
This is no easy task. You can wash the fixer away with water; however, unaided
it will take a long time because fixer is not totally water soluble. To expedite
washing, use a fixer remover, a chemical that converts fixer to a compound
that washes away more easily. After the film has been treated in fixer remover,
you complete the wash with a short rinse under running water.
Fixer removers come in powder form, but they are packaged most commonly
as liquid solutions. Dilutions vary, so follow instructions on the package or
bottle. Some fixer removers come with an indicator dye that changes color as
the solution gets depleted.
Wetting agent. After you have thoroughly washed the film, you can hang it by
a clip or spring-type clothespin to dry. However, water may cling to the film as
it dries and leave streaks or spots on the surface. To minimize this residue, use
a wetting agent so it does not bead up and form droplets.
The wetting agent, also known by the popular brand name Photo Flo, comes
as a highly concentrated liquid. Dilute it heavily, using about half a capful for
a 32-oz or 1-liter working solution.
Setting Up the Chemicals
Set up five containers of working solutions: one each of developer, stop bath,
fixer, fixer remover, and wetting agent. Use graduates or beakers for this
purpose, if they are available, because they have markings on the side for easy
measuring. And be sure to mix enough of each solution to fully fill your
processing tank. Instructions that are packaged with your tank, or printed on
the bottom of some plastic models, indicate how much solution you need. If
your tank has no instructions, fill the tank with empty reels and water. Then
pour the water into a beaker to see what volume of solution is needed to fill the
tank. Even if you are processing fewer rolls than a tank allows, it’s a good idea
to fill the tank fully with solution.
You can use various solution temperatures to process film. It’s best to keep
within a range of 68–72°F (20–22°C), but anywhere from 65–75°F (18–24°C)
is usually okay. The temperature has an important effect on processing times;
the warmer the solution, the shorter the time.
Try hard to keep all solution temperatures consistent, from developer through
fixer and even in the final wash steps. A variation of a few degrees probably
won’t matter, but too much variation can lead to noticeably increased grain in