More about film developing

Stop clock

Film developing background informations

Follow the link below for ADOX CHS processing times:

ADOX Developing timetable.

Please note that all times indicated on any developing timetable in the world are to be considered starting values only.

There are many factors influencing the development process.
If you wanted to take a given time as fixed number you would need to make sure that you:

  • use the same water
  • have your thermometers synchronized
  • use the same measuring devices in the same way
  • have the same cleanliness of all storage containers and film tanks
  • use the same tank model of the same age
  • use the same “arm and hand” to shake the tank the exact same way
  • have the same ambient room temperature
  • use developer concentrate of the exact same batch, storage time and having kept it under the same conditions than the person who calculated the time in the timetable

Since this is impossible to do you almost always need to adjust the time for your own personal conditions.

We are writing this here so extensively not to scare you away or bore those people who are knowledgeable about this but rather because we have received quite some „complaints“ from customers new to the darkroom.
They took the time written in the table as „Gods spoken word“ and developed over and over again with the same time one film after the other with poor results and finally sent all 10 films back to us with a letter stating that „this film does not work it is always to contrasty!“

Other customers started to keep changing things (bad idea if something´s wrong). So when they got e.g. a thin negative from a CHS 100 film in ATOMAL 49 @ 8 mins instead of just adjusting the developing time they started to use a different developer or film or even both. Sometimes you get lucky and the new combination „fixes“ by accident your problem but in general nothing has to be wrong neither with the film nor with the developer or your gear if your first film comes out too thin or too dense.

All you need to do is to adjust the developing time from whatever table on the next roll by changing it while keeping everything else constant.

Here´s the simple formulary:

  • If the neg´s too thin extend the developing time
  • If the neg´s too dense/hard shorten it

You should increase the developing time in steady factors rather than in minutes.
Usually you can start with variations of 10% unless you see that the neg´s much off then you can try a stronger factor.
The reason behind this is that some films need 6 minutes and others need 18 minutes. 10% of 18 minutes is about 2 minutes while 10% applied to 6 minutes is about 35 seconds.
If you increased both by a minute your short developing time is extended by much more than your long developing time.

While you are adjusting one factor always keep all other factors constant!

Never change two factors at a time.
This just confuses you and in the end you don´t know what actually did the trick now.

So you keep

  • the temperature
  • the dilution ratio
  • the developer
  • the film
  • the agitation rhythm
  • the room temperature (!)
  • the exposure of the film in the camera(!)

all constant while only changing the devtime (=developing time).

How to determine if a film is over or underdeveloped

In order to use the „simple formulary“ you need to be able to differentiate an under/over developed negative from an under/overexposed negative!
To some extend over or underexposed negatives can be compensated by changing the paper grade but this is something you should try after you know how to create a correctly developed negative.

The best way to figure this out is to make a print from your negative on a grade 2 paper.
If your negative is developed correctly it should print on a grade 2 paper (or on a multigrade paper with the filter 2 in the filter drawer or the corresponding filter values chosen on your colour head) with the full tonal scale. You are allowed to change the exposure time when figuring this out but you need to keep everything else constant (does this sound familiar?).

Just to be on the safeside here´s what you need to keep constant on the printing side:

  • the paper
  • the filter settings on the multigrade/colour head
  • the developer
  • the developing time (Important!)
  • the developer temperature
  • the safelight (you also have to do a safelight test if this is your first time in the lab)
  • the white light to check on the result (don´t try to judge a print under red safelight- won´t work. Promise)

You are allowed to change the exposure time by varying the time on your enlarger timer.

When your print is as good as you can produce it wash it and dry it.
You will notice that the dried print is darker than it was when wet so you want to aim a bit lighter when judging the print swimming in the fixer.

Lay out the final print under good daylight conditions to make a judgement.

A good print from a perfect negative should show bright white, deep black and all shades of grey on a grade 2 paper.

If the print is too dark overall or too white you need to adjust your exposure time.

If it just can´t be made to look good just using the time start changing the filter or switch to a different grade.

If this does the fix your negative needs to be developed differently.

  • If you had to go higher with the paper grade (3,4,5) your negative was underdeveloped
  • If you need to go lower with your paper grade (1,0) your negative was overdeveloped

If you can´t get it right with changing the paper grade your negative was either off by too far or under/overexposed or both.

A good indicator for an underexposed negative is if the film tip (the part of the film that was sticking out of the cartridge when you put the film in your camera) of a 35mm film is black, the frame numbers exposed onto the film by the manufacturer are clearly visible and well developed but your images are too thin and nowhere on your film is any part in your images really black.

If the images are not really black but neither is the film tip nor the frame numbers you seem to have exposed right but the film is underdeveloped.
In order to make a good judgement use normal negatives exposed neither in bright sunlight nor under extreme low contrast conditions such as fogg in the morning.

Your film is most likely overexposed if the film´s tip is less dark than areas in your images.
However it is difficult to judge an overexposed film from an overdeveloped film. Sometimes you have to find out by dramatically decreasing the developing time or shooting a new roll by using „bracketing“ which means you expose the same image 3 times changing the exposure. The first frame you shoot at minus 1 (one f-stop less than your lightmeter indicates) the second frame you shoot exactly how your lightmeter indicates and the last one plus one which is one f-stop plus.
Note: The larger the number on the f-stop dial the less light penetrates your lens and falls onto your film. So if you want to expose one f-stop plus you have to chose the next lower number e.g. you change the setting from f11 to f8. If in doubt just look through your lens from the back of your camera body with the shutter opened at „B“ and play with the f-stop dial. Keep pressing the shutter release at „B“ to keep the shutter opened. Obviously you want to do this with no film in the camera.

When you have shot and developed a roll exposed with bracketing try to judge which negative is always the best from the set of three.

  • If it is the first (underexposed by 1 stop) your camera lightmeter tends to overexpose your film and you need to adjust it (e.g. by selecting 400 ASA for a 200 ASA roll of film).
  • If it is the middle negative your lightmeter reads correctly and your development is off.
  • If it is the last negative (overexposed by 1 stop) your camera lightmeter tends to underexpose the film (which most lightmeters do) and you need to adjust it (e.g. by selecting 200 ASA for a 400 ASA roll of iflm)

Producing a good and easy to print negative is the goal of any black and white photographer.
You don´t want to produce contrasty negatives even if you like this in the beginning. Your taste will most likely change over the years once you get to know how great a black and white photograph can look if all is perfectly worked out. If you have bad negatives from your first years in the darkroom you can forget about these prints forever.

Try to produce a good negative and play around with the grades on your paper, try lith printing or hard working developers or toners to create special effects.

(C) ADOX Fotowerke, 2011. Mirko Böddecker.