5 Tips for using Fixers
02/10/18 22:44 Filed in: Fixing
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. "Fixing" the photographic negative or print removes the undeveloped (and therefore unexposed) silver halides from the image. If we didn't "fix" paper then the image would deteriorate quickly through time. With film it's actually opaque until fixed. There's things to know about fixing so here's 5 tips.
When I first developed films and paper, I was eight years old. My father showed me what to do and explained that you fix the film for two minutes. Then, when I processed the paper he had me fix it for two minutes also! That seemed easy enough right? But little did I know there was a lot more to it. I was only scratching the surface of fixing. So today I pulled together a few of my favourite tips for my readers.
Tip 1: Dilute fix for film and paper differently.
Film and paper use very different amounts of silver halide in their emulsion film having around 5 times more density of halide crystals than paper *. It makes sense then that in order to remove the undeveloped silver halides in film you need a stronger fixer. Film also contains the halide silver iodide, the hardest of the halides for the fix to remove. This again necessitates a much stronger fix solution to remove. A strong fix solution has a mild bleaching effect that can spoil the delicate highlights in paper if left for too long. Using a weaker solution with paper helps mitigate that bleaching effect. Therefore, use fix for film at 1+4 and fix for paper at 1+9.
Chemistry of Photography - Chris Haslego
Tip 2: Never reuse a film fix for paper.
Some people want to use the same batch of fix for film for the paper! Be warned, it might seem to work, but it is unwise. Film, due to the approximate 5 times higher concentration of silver halides in the emulsion creates much more dissolved byproducts* (especially the difficult to fix silver iodide that is present in film but not paper **). These dissolved halides (not to mention dyes used in film emulsions) can ultimately stain paper or seriously reduce its archival quality. This might not happen straight away, leaving you with a false sense of security, but sometimes years down the line it'll bite you. Keep your fix batch for film separate from your fix batch for paper. Never fix more than the makers capacity (see the fix instructions).
* Post Development Processing
©Copyright 1998 by Dr. Michael J. Gudzinowicz
** "All of our papers are coated with emulsions consisting of crystals formed from a mixture of silver chloride and silver bromide (referred to as chloro-bromo emulsions).
Our films use emulsions consisting of crystals that are a mixture of silver bromide and silver iodide (iodo-bromo emulsions)."
Tip 3: Don't use hypo with modern films.
Back in the day we used sodium thiosulphate or "hypo" to fix film and paper. But, in those days film was different, simpler, and hypo could do a great job. Modern T-grain films such as Ilford Delta and (especially) Kodak T-Max need a more powerful fixing agent to dissolve out the higher amount of the Iodide halides. The older hypo struggles and instead we would be wise to use ammonium thiosulphate. The modern so called 'rapid' fixers use this chemical. So, if you are using older films like Ilford FP4+, PanF+, HP5+ or Kodak Tri-X, and you want to make your own fix cheaply, you can use the sodium fix, otherwise go with the rapid fixers. Oh, the older hypo fix does a fine job with paper which has changed little over time.
Tip 4: Use alkaline or neutral fixers for staining developers.
I use pyro and pyrocatechin staining developers such as PMK, Pyrocat-HD and 510-Pyro. They always put a smile on my face whenever I print negatives with beautiful high tones. These high subtle nuances are difficult to obtain with normal metol based developers. The quality of the high tones is due to the delicate stain left by the developer on the negative. This stain is crucial to the advantages of these pyro developers. Acidic (or what you might call normal) fixers reduce this stain. Therefore use a neutral or alkali fix like TF-2, TF-3, or TF-4. I give two formulas in my book to help.
Tip 5: Alkaline fix = Archival photographs.
I encourage all my darkroom friends to use an alkali fixer for their work whether they use staining developers or not and I favour its use for paper fixing. This is because alkali fixers wash out of the film and paper emulsion much more readily therefore supporting archival quality. Any fix that is not washed from the negative or paper will, with time, leave unsightly stains and ruin the photograph. I, for one, want my photographs to last a long time so archival permanence is important. No brown and unsightly stains on my negatives or photographs! Alkaline fix is the rule of the day. I hope it is for you too!