Check the fixer by putting a piece of exposed film (the end of the exposed film you cut off to load the roll?) into the fix and time how long it takes for the film to go clear.
This time should be doubled to ensure proper fixing. As the fixer becomes exhausted this time will increase, when it gets too long it's time to change the fix.
Does it not mention this in the fixer instructions.
HTH
David
i use fixer if the clearing time is up to a minute ( ish ),any longer and i make some more
Not a criticism... but it's not essential. I don't use stop with film, just water.
Steve.
All these answers are correct..
a stop bath serves two purposes First it stops further development almost instantly, which is useful with short development times. secondly it neutralises the alkali in the developer so fixer remains acidic, and works for longer.
Fixer can contain sodium thiosulphate (hypo) or ammonium thiosulphate (quick fix) or indeed a mixture of both. It also contains an acidic stabiliser such as sodium metabisulphite. (weakly acidic)
The two main types of fixer have very different clearing times, but double that time in each case will ensure a complete removal of the remaining silver halide.
If films do not clear completely in a reasonable time, it is time to replace the fixer. (Often also indicated by a sulphurous smell.)
As vital as any other part of the process is thorough washing, as residual chemicals can seriously reduce the archival quality of the film.
Over fixing in ammonium thiosulphate by extending the time, can start to bleach the black silver in the film and is not advisable.
The proportion of Water in fixer plays a vital role and using it too strong can reduce the effectiveness of Hypo. don't be tempted to add more for luck, it will just waste money.
