TF4 for paper - Leader clip test works for paper?

I use TF4 fixer mixed for B&W paper. Can I use a "leader film" clip test to see if the fixer still has capacity left for paper?

It cleared a leader clip in 30 seconds...does that make it still good for paper?

Thanks!

I don't recommend that you use the same batch of fixer for film and paper. Using the same type of fixer at different dilutions for film and paper is fine. Particularly toublesome is using fixer that you've used for fiber based paper on film. The fixer can pick up of lint from the paer and deposit it onto the film. Normal washing after fixing will usually take care of the problem, but why ask for trouble?

A film leader clearing in 30 seconds is fast in anyone's book, and indicates that there is plenty of capacity there to clear a print. But there is a better way to do a clip test with some control.

Different films will have different clearing times in the same fixer, and different types of fixer will yield different clearing times with a give type of film. You need to eliminate both variables from your testing procedure if it is to yield any meaningful information. An extreme example would be a comparison between one of Kodak's TMax films and one of Foma's films. TMax films are notoriously difficult to fix out completely. Foma films fix out, by comparison, in a flash. Get a roll or two of the cheapest, crappiest B&W film you can find and use it for a fixer test. Take a small piece of film and place one drop of FRESH fixer onto the emulsion side. After 30 seconds, immerse the film chip into a small container of fresh fixer and agitate continuously. Note the total time it takes for the entire film chip to clear. The spot where you placed one drop of fixer for the initial 30 seconds will clear first and will serve as a visual reference to confirm that the remainder of the film is cleared. Now subtract 30 seconds from the total time to determine the clearing time for a given film in a given batch fresh fixer. When that clearing time approaches 2x the fresh fixer time, the fixer should be discarded.

I don't use the same fixer for paper and film...but was wondering how I can see if my paper fixer had life left in it, since I haven't been counting paper sheets or square inches.

I just wondered whether a "film clip test" could be used to judge the life left in a "paper fixer"...

Thanks for the film tip...

It seems to be a good first-approximation test. I do this, but also use silver test strips from Tetenal. I find a silver build-up of 1mg/l happens well before the fixer is exhausted. Ilford recommend keeping silver in the fixer under 0.5mg/l for "archival" prints and 2mg/l for "commercial" work with fibre paper. I've no idea how realistic this is. 0.5g/l is very little indeed: about 10 8x10"s per litre of fresh fixer. I have not tested exactly (and I assume it is not a fixed relationship in any case as you are measuring two different properties) but probably a good time to discard the fixer is when the leader test gives an increase of 50% in clearing time. I always use a piece of FP4+ for the test and the fixer is Agfa FX Universal.

Cheers, Bob.

I'll add something to the mix.

For fixer intended to be used with paper, use paper clips, he, he! Seriously, cut up one inch squares of unexposed paper you are using. Turn on the room lights since safe light is not needed. Now mark each square on the back 5 sec, 10 sec, 15 sec, 30 sec, and 45 sec. Make sure they have been exposed to room light. Fix each square for the indicated time, wash, and then put them in developer. The squares will show varying degrees of developed sliver, the one that is all paper white has been completely fixed.

It is an interesting experiment, but if it is really valid I couldn't say for sure.

T

As an economy I keep fixer I have used on films and use it to fix my test prints. For exhibition/sale prints I always use fresh developer and fixer on a one shot basis.

Correction: that should be "g/l" not "mg/l" above (what's two orders of magnitude between friends?)....

Bob.