Anybody know about how much of this I add to turn regular fixer into rapid fixer? I was going to buy some bulk sodium thiosulphate to make my own fixer and then use ammoium chloride to turn it into the rapid fix, rather than make rapid fix up from scratch using 60% ammoium thiosulphate.
You might check out Steve Anchell's Darkroom Cookbook". If you are in to mixing from bulk it is a great referrence. I have two. One at home, the other at school.
I did a quick review for you and in the formulas for rapid fixer he list 50 grams per liter.
From Darkroom Pro's site:
Kodak's F-7 Rapid Fixer
Sod. Thiosulfate 360g
Amm. Chloride 50g
Acetic Acid (28%) 48ml
Boric Acid 7.5g
Pot. Alum 15g
Water to make 1.0L
This is a standard rapid fix with all the hardening mixed in. Fixing times are 5 min. at 70 F for T-Max films.
If you don't want hardening, look for Kodak F-8
I use a similar formula - but with ammonium sulphate (that's whai I found at the chemist).
Just looked in the cookbook and the Sodium Thiosulfate to Ammonium Chloride ratio is 4:1. If I take the TF-2 recipe and add ammonium chloride in this same ratio, will it do the trick? Just wondering if anyone's ever tried it so that I won't be wasting my time in mixing it up. Thanks!
My film fixer is similar to your idea - but I've made it just a bit acid (since I do not use a stopbath - just water.
Kodak Rapid Fixing Bath F-9 (modified)
Water, about 125F (50C) 600 ml
Sodium thiosulfate pentahydrate 360 g
Ammonium sulfate 60 g
Sodium sulfite, desiccated 15 g
Sodium metabissulfite 10g
The paper fixer is TF-2 but with borax in place of metaborate (I don't use a stop also, just water).
I use something similar:
Sodium Thiosulfate 250g
Sodium Sulfite 15g
Sodium Metaborate 100ml (10% solution)
Ammonium Chloride 20g
to 1 liter finished solution.
There's less Ammonium Chloride htan in the cookbook recipes, but it's enough that a piece of film clears in less than 20 seconds.
I don't measure out the chloride, just add 3 teapoons. I lust went and weighed it, and it comes to about 20g...