Alternative fixers

Salt as fixer

Published 23rd March, 2012
It is more or less a myth that common salt (Sodium Chloride) can be used as fixer. I tried it and... it works under certain circunstances.
The recipe:

• 300g salt (Sodium Chloride) per liter solution minimum

• 0,2 g Potassium Bromide per liter

Preparation:
Put 300g salt in a beaker and some 700ml water, stir until most of the salt is dissolved. Add water to
make 1 Liter and go on stirring until the salt is completely dissolved. The final density of the water
should be 1,2 g/cm3. Add 0,2g of KBr, Potassium Bromide.
Usage:
After the development of the film and rinse with water, fill the tank with the salt solution. After one
hour you may open and control the fixing process. It will take some 5 hours to complete at room
temperature, but only 1 1/2 hours if warmed around 40ºC.
Note: I used sodium chloride from sea with Fomapan 100 ASA

Review on 20th April, 2012
Review on 15 August, 2012

Ammonia as fixer

Another unusual substitute for fixer is ammonia that should be used pure. It works fast, but it may not fix completely if the emulsion has Silver Iodide.

Important notice about ammonia as fixer:

I found this in the Wikipedia:

«... silver chloride (AgCl) is soluble in dilute (2M) ammonia solution, silver bromide (AgBr) is only soluble in concentrated ammonia solution, whereas silver iodide (AgI) is insoluble in aqueous ammonia.»

Potassium Thiosulfate

Sodium Thiosulfate and Ammonium Thiosulfate are the most common fixers used. But other thiosulfates may also be used, such as Potassium, Calcium or Magnesium Thiosulfates. Thiosulfates are used as fertilizers, Sulphur doners. Liquid fertilizers are often thiosulfates, just check the composition if you find them in a shop.

Thiosulfates may also be prepared by boiling a sulfite, bisulfite and metabisulfite with Sulphur.

Salt fixer, improved! (New)

Since I rediscovered salt as a slow fixer, in 2012, nothing changed until now (13.08.2015).

The new recipe:

300 g/l salt

4g/l Potassium Bromide

2 ml/l of a 5% solution of Sodium Hypochlorite (household bleach)

Preparation of 500ml:

Put 150 g of salt in a heat resistant beaker and add 550 ml of hot water and stir for several minutes until most of the salt is dissolved. Filter with coffee filter (this is an important step to prevent recrystallization of salt). Add 2 g of Potassium Bromide and 1 ml of 5% Sodium Hypochlorite (or 20 drops).

This new version of the salf fixer is more than 3 times faster than the first 2012 version. Using temperatures of 30 degrees Celsius, it is possible to fix normal films in a few hours, 2-4 hours. T grain films couldn't be fixed with the first version but with this new version and using temperature, after 6 to 10 hours the work is done.

First published in 13.08.2015

Mixed fixer, Potassium & Sodium Thiosulfates

Recipe:

100 g Potassium Metabisulfite
36 g Sodium Hydroxide
29 g Sulfur

Preparation:

First dissolve separately the Metabisulfite and Hydroxide, each in about 500 ml water. Then pour the Hydroxide solution on the Metabisulfite. In this step you are preparing a mix of Potassium and Sodium Sulfites, according to:

K₂S₂O₅ + 2 NaOH = K₂SO₃ + Na₂SO₃ + H₂O

Bring this 1 liter solution to the fire and when it starts boiling lower the flame and add the 29 g of Sulfur. Let it boil slowly and stir. At a certain point the Sulfur sinks to the bottom. Wait some more minutes and then switch off the fire. Let it cool and filter the solution with coffee filter. Not all Sulfur reacts, but you will end with Potassium and Sodium Thiosulfate and the remaining unreacted Sulfites.

If all Sulfites had reacted the overall reaction would be:

K₂S₂O₅ + 2 NaOH + 2 S = K₂S₂O₃ + Na₂S₂O₃ + H₂O

Usage:

Use the solution you got, about 700-800 ml, undiluted. It takes 5 minutes to fix for normal grain films and 15 minutes for T grain films.

First posted on 17-08-2015

Murray Kelly's suggestion for a rapid fixer

My friend, Murray Kelly, have told me that adding Ammonium Sulfate to Sodium Thiosulfate would turn the last into a rapid fixer like Ammonium Thiosulfate.

I suppose that this mix may be seen as producing Ammonium Thiosulfate, as shown by the balanced equation, here.

For 1 liter solution, you may use 200 g Sodium Thiosulfate and 100 g Ammonium Sulfate.

Sodium Thiosulfate is the classic Hypo and is easy to get, also at ebay.

Ammonium Sulfate is a common cheap fertilizer and may be found at agriculture shops.