Using Fixers with film (paper fixing below)
Fixing? Surely there's nothing to it right? I mean, you just dump the film or paper into the fixer after stop bath, swish it around for a couple of minutes and wash right? Well my friend, you couldn't be more wrong.
First the basics
Although you can use the same fixer formulas for both film and paper, their working strengths might be very different. Read the dilution instructions carefully.
And another thing, never use a fixer that has processed film for subsequent paper processing. The silver by-products from fixing film will adversely effect your paper.
Some fixers are termed as 'rapid'. Rapid fixers contain Ammonia Thiosulphate, a powerful fixing agent. Older ‘normal’ fixers contain Sodium Thiosulphate, commonly known as Hypo. Don't use the older Sodium Thiosulphate fixers with modern T-grain films (like Kodak T-Max and Ilford Delta, Acros) because it does not fully fix the emulsion.
Then there's alkaline fixers and acid fixers. Many photographers are moving to alkaline fixers because they:
a. Wash out of the film more quickly and
b. Have a less bleaching effect on Pyro stain.
Frankly, I would advise you to use alkaline fixers all the time for your films and certainly for paper if you cannot guarantee that you are washing them to archival permanence. If there's any fix or fix by products left in the film or paper then it will deteriorate. You've seen those old brown photographs from years ago? They were not washed correctly and the residues turn the paper brown. (Ever seen a brown Ansel Adams? He knew how to wash prints). Alkaline fixers wash out of the emulsion (both film and paper) much more effectively and quickly.
There's some well known formulas for alkaline fixers and I have included them elsewhere on this site. There's also TF-4, designed by Bill Troop, and a first class fix. You can purchase it from the Formulary.
The times described for the fixing of films must be used only as a guide. To measure an accurate fixing time for film:
- Keeping the developing tank shut, pour in the fix and gently agitate for 30 seconds
- Open the developing tank and pull out the spool
- Examine the film, looking for milkiness/cloudiness in the emulsion. It is easy to see without removing the film from the reel. It literally looks white like a white layer
- Continue agitation by gently dunking the spool in and out of the fix in the tank, watching for the milkiness to go
- Note the time when the white milkiness in the emulsion disappears (this is called the clearing time)
- Continue to fix for a total of three times this clearing time
- Pour the fix back into a storage container for re-use
The first time that you use a fresh batch of film fix you should write the clearing time on the bottle.
With fresh solutions you may find that after 30 seconds the film is already clear.
If this is the case, fix for a total of two minutes. One liter of working strength fixer should be good for between 10 and 20 films. You will notice the clearing time getting longer as the fixer becomes more and more exhausted. When it takes twice the length of time to fix the film as it did when the solution was newly made, discard the fix and make fresh. For me this is usually when the milkiness takes 1 minute to clear (and I have therefore reached the two minute minimum fix time).