Film Photography: How long does fixer last?
This is the first of a series of short posts to dispel some of the myths I have come across when teaching myself film photography and more specifically developing black and white film.
Question: How long will fixer keep for once it has been diluted?
(I will use Kodak T-max fixer as an example, diluted 1:4 with water, as this is the fixer I use). I’ve read many different answers to this question but the most common one appears to be dump the developer after each roll of film developed. I develop my own black and white film partly because it is more economical. If I was to dump my fixer after every roll of film home developing would soon prove expensive.
Answer: Longer than you think..
(Based on my own experience)
I made up a diluted batch of 1.5L of diluted T-max fixer 4 months ago and have stored it in a dark cupboard in a clear soft drinks bottle. The bottle is not full to the top so air is in the bottle. Since making the batch of fixer I think I have developed roughly 25 rolls of B&W film (mostly 120 film but the occasional 135 also). I tend to leave the film in the fixer for a longer period than suggested to be safe (20 minutes) but I have not observed any problems so far.
Here is an example from the last roll of film developed:
Yulya, Ukraine with ARAX-CM medium format camera & Kodak T-max 400
*I have read that diluted fixer can be used for as long as six months but so far I have not reached that stage.
Fixer shelf life – Conclusion
Even if you want to play it safe and make up a new batch of fixer every month it will still be much cheaper than making a new batch after each roll.
More film myth breakers coming soon..
How to tell if fixer is still good? Quick test.
A quick test to see if your fixer is still good is to put a piece of undeveloped film into the fixer dilution. Swill the fixer solution around with the piece of film in and the film should go transparent within a few seconds. If the film stays opaque then the fixer needs replacing.
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Does fixer even go bad at all? Doesn’t it just get exhausted? I use it as long as it’s not exhausted and haven’t had any problems, yet. Even storing it for months didn’t really matter.
It’s easy to mix your own test chemicals: https://www.digitaltruth.com/
Hey, thanks for the chemical test check… I must try that. I think when people term fixer as gone ‘bad’ it means exhausted. This is what I was referring too. Cheers!
I mix my own fixer from chemicals. Fixing should be rapid. (Reasons: longer fixing > longer the washing > more vulnerable emulsion; the longer the fixing, the more silver it eats that you may want to keep.) My films clear after 1:30 to 2 minutes (with agitation). Then add the same time = total 3 to 4 minutes, no more than 5! As urbanhafner said: Fixer does not go bad (if correctly prepared), it exhausts. How to tell? As you say Matt, test with a snippet of unexposed film. If normal time to clear is 2 minutes but now it takes 3 minutes: Time to prepare new fixer. It is not a good idea to economise on fixer by prolonging fixing time.
No offense, but some of these statements are incorrect. Fixing film for extremely long periods like 20 minutes can cause changes that can affect permanence of the image.
The correct time to fix film is usually given as twice the time it takes the film to clear (some authorities now say 3 times for modern films). You determine the clearing time by putting a piece of scrap film in the fixer, agitating it, and seeing how long it takes the film to become clear. (For me, with brand new Kodak Rapid Fixer, that’s about thirty seconds).
Clearing time is also how you tell that the fixer is wearing out. The clearing time will become longer and longer as the fixer gets old. When you reach the point where it takes twice as long as it did with fresh fixer, it’s time to discard that fixer.
Hi thank you. I am self taught so I just share what I tend to do. I’ve always fixed for 7-10mins (casually) as my fixer isn’t fresh each time so more of a safety measure. I do test strips before now to check the fixer still works but good to know that you can fix too long. Many thanks!