Film development consists of a series of steps, always done
in the same order: pre-wash, developer, stop bath, fixer, hypo-clearing agent,
and wash. Each step except for
washing should be done with the film in complete darkness (that is, in an
enclosed tank with a light trap, or in a completely dark room). Each step requires a different chemical solution.
Temperature of the solutions, particularly the developer, is important,
and a water bath should be used to keep the temperature of the chemicals and the
film tank all uniform and constant.
Film can be developed in hand tanks, in small
semi-automated/fully-automated roller processors like those made by Jobo, and in
commercial style continuous or dip-and-dunk processors.
Unless you are processing very large quantities of film, the commercial
style processors don’t make economic sense, and your choices are to either use
hand tanks or a roller processor.
Roller processors generally automate the agitation,
and may automate changing of chemistry, and thus make film development very
repeatable and reduce the effort greatly. Hand
tanks, however, are perfectly capable of delivering excellent results and are
much cheaper. In both cases the
film is generally loaded onto reels and the reels are placed in a light tight
tank, so the two methods are very similar.
Roll film (35mm and 120/220) is generally developed on
reels that fit into light tight tanks. The
reels are either plastic or stainless steel.
Plastic reels are more easily loaded by beginners but cannot be loaded
when wet. Stainless reels
(particularly cheap ones) can be hard to load.
High quality stainless steel reels are substantially easier to load than
cheap ones because the spirals are better aligned.
I use plastic reels in Jobo tanks when I develop film in a Jobo
processor, and use stainless steel reels in stainless steel tanks when
developing film in a hand tank. I
find that the best stainless steels reels are those made by Hewes in England.
Hewes reels are sold under the Jobo name (among others) in the US.
Loading the film onto the reels must be done in complete
darkness, without a safelight. Generally,
roll film tanks are equipped with light traps in the lid, so that solutions can
be poured in and out with the room lights on.
To open a 35mm film cassette, pry the end cap off
with a bottle opener. I find it
helpful to trim the film leader off when loading film onto plastic reels.
Trimming the corners of the leader end will make the film slide into the
plastic reel more smoothly. When
the entire film is on the reel, cut the spool off the film and then wind the
film all the way onto the reel.
With stainless steel reels, I still cut the leader
off (to make it easier to hook the film onto the clips in the center of the
reel) but there’s no point to trimming the corners.
Generally it’s helpful to turn the reel with one hand while letting the
film run through the other hand as it winds onto the reel.
Regardless of whether you use plastic or stainless steel
reels, loading film onto
reels takes a bit of practice, so it’s wise to practice in the light with a
worthless roll of film before venturing into the dark to load valuable film.
Once the film is on the reel, and the lid is on the tank,
it’s safe to turn on the room lights. The
light trap in the tank lid will allow you to pour chemicals into and out of the
tank and will prevent light from entering the tank and fogging the film.
Good hand tanks have light traps that allow the
chemicals to be poured in and poured out quickly.
Before processing film in a tank for the first time, it’s not a bad
idea to experiment a little, pouring water in and out of the tank (with nothing
in the tank) so that you get a feel for how quickly you can pour chemicals in
and not have it back up and spill.
After pouring chemicals into the tank, it’s a good
idea is to rap the tank on the counter (or sink bottom) several times to
dislodge any air bubbles that might be clinging to the film.
Agitation
Consistent agitation is important to getting good results.
If you agitate too little, development will be uneven.
If you agitate too much, it will increase the rate of development.
A good rule of thumb is to agitate continuously for the first 30 seconds
and then agitate for five seconds twice per minute.
For developing film with hand tanks, a good agitation
method is to invert the tank gently 3-5 times in a five second period.
Make sure you put the water-tight lid on the tank before you start
agitating.
Capacity
It’s important to know the capacity of the tank you use.
If you put in too much liquid, you may not get proper agitation and the
result will be uneven development. If
you put in too little, the chemicals will not cover the film, and you’ll end
up with only part of the roll developed. Typically,
this will ruin the entire roll of film.
Generally, all manufacturers produce black and white
processing chemicals which are identical in result if not in composition.
This is true of fixer, stop bath, and wash aids like Hypo Clearing Agent.
It is not true, however, of the developer, and cults have formed around
the use of various arcane developers. Generally
speaking, most developers will produce decent results with most films.
Several developers are excellent general purpose choices and can be
relied on to produce excellent results with virtually any film.
D-76/ID-11
D-76 is probably the single most used developer for black
and white work. D-76 is the version
marketed by Kodak. ID-11, sold by
Ilford, is an identical formulation. D-76
comes as a powder, which you dissolve in water to produce what is called the
‘stock’ solution.
Many people use D-76 diluted 1+1, which means that
you mix the stock solution and water in equal parts to produce the working
solution. When used in this way,
D-76 produces slightly sharper negatives and very slightly larger grain.
Tmax
Tmax developer was produced by Kodak to be
used primarily when ‘pushing’ film. Pushing
means over-developing film to compensate for underexposing it.
Although it can be used for general film developing, it's probably
not the best choice.
Tmax-RS
Despite the name similarity to
Tmax developer, Tmax-RS is a different developer. It produces
moderate grain and excellent tonality when diluted 1+9, and I use this
combination for developing all my 4x5 film.
XTOL
XTOL is a developer recently introduced by Kodak, and
includes sodium isoascorbate (vitamin C) as a developing agent.
It produces very fine grain, a pleasing tonal distribution like that of
D-76, and comes as a powder than can be more easily dissolved than D-76.
XTOL is an excellent choice for a general-purpose developer.
HC-110
HC-110 is a general-purpose film developer that comes as a
liquid concentrate (and thus is more pleasant to use than the powders).
It produces fine grain and good sharpness, and is widely used.
Rodinal
Rodinal is one of the oldest developer formulations, and is
still widely used. It produces
fairly large grain but very high sharpness.
Rodinal comes as a liquid concentrate which can be stored for long
periods without going bad.
Stop
Bath
Stop bath for film development is generally a dilute
solution of acetic acid. Acetic
acid is essentially very pure white vinegar.
Some people have a strong dislike for the smell of acetic acid and use
citric acid instead.
Kodak markets a popular stop bath which consists of
acetic acid and an indicator that turns from yellow to purple when the stop bath
is exhausted. Stop bath is so
cheap, however, that it makes little sense to use it more than once, and I find
that the simplest thing is to buy acetic acid in bulk and dilute it.
Some people like the indicator stop because the yellow indicator gives it
a very distinctive color which can prevent confusion in the darkroom.
Fixer
For film development, it’s best to use an ammonium
thiosulphate based ‘rapid’ fixer. This
is particularly true for Kodak’s Tmax films, which are very hard on fixer.
I generally use Kodak Rapid Fixer. Heico’s NH-5 is essentially the same product and is slightly cheaper
when bought in quantity.
Hypo
Clearing Agent
Using a wash aid like Kodak’s Hypo Clearing Agent will
substantially reduce the time and water needed to wash film after development.
Most companies produce some sort of wash aid in their lineup.
I use either Kodak Hypo Clearing Agent or Heico Permawash, whichever is
currently cheapest. Permawash has
the advantage that it comes as a liquid concentrate, which is easier to handle.
The pre-wash (sometimes called the ‘pre-wet’ or
‘pre-soak’) step serves several functions.
First, it wets the emulsion of the film uniformly, providing for more
even application of the developer during the development step (and thus ensuring
more even development). Second, the
pre-wash helps get the film and the tank to the right temperature and makes
process control easier. By wetting
the film before pouring in the developer, you reduce the risk of air bubbles
that prevent the developer from contacting parts of the film.
Some films, most notably those from Ilford, incorporate wetting agents in
the emulsion and thus do not need (and should not get) a pre-wash step.
The pre-wash step should be done with water at the
same temperature as the developer. During
the pre-wash, various dyes will wash out of the film. Some of these are part of the anti-halation backing of the
film, and others are sensitizing dyes used to control the spectral sensitivity
of the film. Having these dyes wash
out of the film during the pre-wash is perfectly normal, so don’t be surprised
when the pre-wash water comes out of the tank some strange color.
Different films use different dyes, so the pre-wash water will come out
different colors, too.
Developer
The function of the developer is to chemically convert the
silver salts that have been exposed to light to metallic silver.
The temperature and duration of the developer control the rate at which
this chemical reaction occurs, so it’s important to make especially sure that
the developer is the right temperature to start, and to use a water bath to make
sure the temperature doesn’t drift during the development step. It’s
possible to re-use developer, but I generally dilute the developer with water
and use it one shot to promote consistency.
If you re-use developer, you will need to compensate for the developer
becoming exhausted by either replenishing the developer or by extending the
development time. Both methods are
error prone, so I recommend using developer once and then discarding it.
Stop
Bath
The function of the stop bath is to halt development
swiftly (and thus evenly) and to neutralize any remaining developer so that the
alkaline developer won’t change the acidity of the fixer (and thus reduce the
effectiveness of the fixer). It’s
possible to use water for stop bath, but generally a dilute solution of acetic
acid is used (acetic acid is essentially vinegar). The development is halted nearly instantly when the
stop bath contacts the film, so there’s little point in having a stop bath
step longer than about 30 seconds with continuous agitation.
Fixer
The fixer dissolves all of the undeveloped silver salts
from the film, leaving the metallic silver that was produced by the development
step behind. Regular sodium
thiosulphate fixer can be (and is) used for film, but I find that using a ammonium
thiosulphate ‘rapid’ fixer works very well and is especially good for the
‘hard on fixer’ Tmax films. Timing
of the fixer step is not particularly critical as long as fixing is complete –
generally a fix time of 5 minutes with continuous agitation is sufficient. Fixer can be re-used but eventually becomes exhausted, so you
need to either use it one shot, or else you need to track how many rolls have
been through it (or use fixer test solution) and discard it when it starts to
become exhausted.
Hypo
Clearing Agent
The hypo clearing agent serves to help remove the fixer and
fixing by-products from the emulsion, and thus makes the wash step more
effective. The duration of the Hypo
Clearing Agent step is not particularly critical but different products require
different times. Follow the
manufacturer’s directions. Hypo
clearing agents do not store well and become exhausted rapidly, and thus should
be used one time and then discarded.
Wash
If fixer remains in the emulsion, it will eventually
destroy the negatives, so it’s important to wash the film thoroughly.
Fortunately, the emulsion on all modern films is thin, and the film base
itself does not absorb fixer, so wash times can be short – typically around
five minutes in running water. Generally
it’s a good idea to use wash water as close to the temperature of the
developer as possible. Colder water will be less effective at washing the
film, and water that is too hot will damage the emulsion.
Dry
While film is drying, the surface is very tacky and dust
will stick to it and become a permanent part of the film.
Since any dust on the negative will appear as white spots on prints, this
is generally considered to be a Very Bad Thing.
One way to get around this is to use a film dryer which
blows warm, filtered air over the film to dry it rapidly.
Another way is to hang the film to dry in a quiet, dust free place, and
then leave it alone until it is thoroughly dry.
One good trick is to run a shower with hot water until it’s steamy, and
then hang the film to dry in the shower stall.
The running shower knocks down all the dust, and the shower stall walls
are generally sufficiently enclosed that they prevent dust from floating in and
sticking to the film.