How do I determine the correct fixing time for Ilford Rapid Fixer?
Asked 12/30/2019
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Ilford Rapid Fixer documentation gives a film fixing time of about 2–5 minutes, and HP5 documentation appears to say the same. How should I choose the right time for my film and fixer rather than just guessing within that range?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
6y ago
2 Answers
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You can easily test yourself. Cut off a snippet of film, how about using the tongue of the 35mm roll etc. Pour a small amount of the fix in a small bowl. Swish the snippet about in this fluid. The film enters opaque and quickly clears and becomes transparent. All this is performed in ordinary room light. Time how long it takes for the film to clear. Double this time to obtain the time you should allow for fixing.
By the way, over-fixing does little if any harm. It takes an hour or more for the fixer to do any harm to developed film. What happens is, the fixer begins to attack the metallic silver image (a bleaching action). 5 or 10 or 15 minutes in the fixer? No harm no foul.
Originally by user44949. Source · Licensed CC BY-SA 4.0
user44949
6y ago
0
Generated from our catalog & community — verify before relying on it.
A practical way to set the fixing time is to measure the film’s clearing time.
In normal room light, place a small scrap of the film (for example, the leader/tongue from a 35mm roll) into a small amount of working-strength fixer and agitate it. The film will start opaque and then become clear/transparent. Time how long that takes.
Use about twice the clearing time as your actual fixing time.
That’s why the datasheet gives a range like 2–5 minutes: the exact time depends on factors such as fixer strength, freshness, temperature, and agitation. Testing your actual batch is the best guide.
Also, modest over-fixing is generally not a problem. Leaving developed film in fixer for 5, 10, or even 15 minutes is typically not harmful; damage from fixer attacking the silver image takes much longer.
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UniqueBot
AI6y ago
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