After reading about this developer on the web I decided it would be worth
trying, especially for roll films. When shooting large format sheet film I
can develop each negative individually to control the brightness range on the
film. That isn't generally the case with roll films. A single roll
may contain images with brightness ranges very different from each other.
How do you process such a roll to achieve acceptable results for all the images?
According to the web review I read one answer might be Diafine.
So what is Diafine? Diafine is a fine grain, full (or greater) film speed developer. It has
some great features.
- It provides almost a full stop of film speed increase versus the
manufacturer's rated speed. (This can be debated but suffice it to say
that if you normally shoot 100Tmax (for instance) at 100 you can achieve
comparable results shooting it at 160.)
- It can be used at any temperature between 70 degrees F and 85 degrees F.
- Development time makes no difference provided the film gets at least three
minutes in each bath.
- Films of different speeds can be developed together in the same tank at
the same time.
- The stuff seems to last forever and can be continually re-used.
- It is a compensating developer. This means that shadows develop
fully with excellent detail and highlights won't be blocked up.
How does Diafine achieve all this? In part by being a two bath
developer. A Diafine kit makes two solutions. Solution A is the developing
agent and solution B is the accelerant. When the film is processed it is
first placed in Solution A. The developer is absorbed into the film's
emulsion layer. After the recommended time of three minutes solution A is
poured back into the bottle. Since it doesn't have any accelerant in it it
doesn't weaken over time. If you leave the film in the solution longer
than three minutes no harm is done. All the developer that the emulsion
can hold is absorbed within three minutes, additional time has no effect.
Next solution B is poured in also for at least three minutes. Solution
B contains the accelerant and causes the developer to begin working. Since
the amount of developer available is only what was absorbed into the emulsion the
development runs to completion, unlike other developers where development is
stopped at some pre-determined point. After three minutes or more solution
B is poured back into the bottle. Since development has run to completion
there is no unused developer left to react with the accelerant in the bottle
(though the accelerant may be slightly weakened in practice this has no effect
As with solution A if the film is left in for more than three minutes no harm
is done. Development runs to completion in three minutes so longer times
in the second solution don't result in over development.
No stop bath need be used, again because development to completion, so fixer
can be poured in immediately after solution B is poured out. Fixing and
washing are done normally. If you re-use your fixer you can use a water
rinse between solution B and the fix to slightly extend the life of the fixer.
One of the great things about two bath development is that the shadows will
develop with great detail and the highlights won't blow out. Highlight
areas which received the most light require more development. The since
the only developer available is what is contained in the emulsion (absorbed
during the first bath) the developer
is exhausted before all the exposed silver in those areas is developed so the
highlights maintain detail and don't block up.
The shadow areas have less exposed silver so there is sufficient developer in
the emulsion to develop those areas completely. This results in excellent
Combining those two effects means that contrast is controlled and the
resulting negatives will have "normal" contrast even if the original
scene had extremely high contrast. Normal contrast scenes are also
rendered beautifully. In my testing I found that low contrast scenes don't
lend themselves to development with Diafine. The resulting negative can be
quite flat. (Update: If low contrast scenes are to be developed
using Diafine I have found that shooting the film at the manufacturer's
recommended ISO setting will allow the resulting negatives to achieve more
So when should you use Diafine? The short answer is "it
depends". If you are using roll film where you can't develop each
negative independently and the contrast range of the original scene was high or
normal then Diafine will give very good results for each negative on the roll.
If you are using sheet film then Diafine can also be used for those negatives
of normal to high contrast scenes. For negatives of low contrast scenes
another developer will probably yield a better result.
Now I would like to make a comment about film speed. The instructions
with Diafine state that most films will receive a speed increase when used with
Diafine. For instance TMax 100 (and now 100 TMax) can be used at ISO 160
rather than 100. In my testing I generally found this to be true, but I
also found that because of the compensating effect of Diafine if film is exposed
at the manufacturer's ISO rating shadow detail is improved and highlights still
don't block up. (Using the manufacturer's ISO rating also allowed me to
use Diafine with negatives of low contrast scenes and get acceptable negatives.)
Because of this I generally shoot at the manufacturer's stated ISO (or at my
personal EI determined by testing with my "regular" developer).
This gives me more flexibility than following the Diafine directions would
allow. I don't have to decide ahead of time that I want to used
Diafine. I can shoot as I would for my normal developer and if I later
decide to use Diafine I can do so without worry.
One last note- Diafine makes developing film almost fun. I have the two
solutions mixed and ready to go in my tempering tray. I just load the film
into the developing tank and pour in solution A. I don't have to worry
about time, temperature or agitation (other than a couple of knocks to dislodge
air bubbles after pouring in the solutions). After three to ten minutes
(yes I've tested times up to ten minutes) in solution A I pour it back into the
bottle and then pour in solution B. After more than three minutes it is
time for the fixer. Simple, fast and actually fun.
The batch I'm currently using has been stored in brown plastic partially full
bottles for over seven months. The remaining solution is poured back into
the appropriate bottle after use. The solutions definitely get discolored
from the anti-halation dye in the film but it doesn't seem to affect them at
all. There are stories of news photographers keeping Diafine solutions in
bottles in their desks for years. I don't doubt it! (Update:
I used my original batch of Diafine for over a year. It was working just
as well at the end of that time as it was at the beginning. The solutions
were stored in regular plastic bottles at darkroom temperature, typically about
70 degrees F in my darkroom. I made no effort to keep the bottles full or
to expel air after use.)