Testing fixer

[degruyl]

Do you test your fixer for saturation, or just use it the recommended number of times, or use it until it stops working and then mix some more?

I am considering adding testing to my workflow, I have been using guesstimate of number of rolls... which is pretty bad, I know.

 

[Pickett Wilson]

Stick a piece of exposed film in it. See how long it takes to clear. Should be about two minutes or less for rapid fixer. Fix film twice the time it takes to clear.

 

[Pickett Wilson]

Roger Hicks might have something on this on his web site. Good source of info on just about anything photo related.

http://www.rogerandfrances.com/

 

[Roger Hicks]

Silver overload is not normally the problem with film: just exhaustion. Go to http://www.rogerandfrances.com/subscription/ps how process 35-120.html and scroll almost to the bottom for a piece on fixer testing.

Thanks for the plug, Pickett!

EDIT: The difference between this and the simple test described by others is that it is MUCH easier to be sure when the film has truly cleared, because you can compare fully cleared and partially cleared film. It adds about 30 seconds to the test.

Cheers,

R.

 

[DGA]

I added a simple fixer test to my workflow recently:
After I have the films safe in the tank I take the lead that I took of, drip a single drop
from the fixer and measure the time it takes for the emulsion to dissolve to a clear circle.
At this point two things may happen:
Either, the circle under the drop becomes clear, then the fixer time should be double the time
the clearing took.
Or, The circle under the drop doesn't seem to get clear, then it's time for a new solution.

Nevertheless, as long as your fixing time is above the double time it takes for the clearing
you are safe.
I sometimes measure 1:30 minutes for a full clear, but eventually fix for 5-6 minutes.
Nothing happens.

Good luck.