Alkaline Fix Longevity

[Mahombi]

Can someone tell me the keeping properties of TF-3 alkaline fix, when mixed to working solution strength and kept in tightly stoppered bottles?

In the past, when using acid fix for film processing, I've always kept two, two litre bottles of working strength solution (for two bath fixing). I've never had any problem with those going off. Does the same apply to TF-3? The alternative, is to mix up the working solution at the time and throw it away after, which seems a bit of a waste.

[Ron Marshall]

I can give you the Kodak data. Kodak rapid fixer, stock keeps indefinately in a full container:

http://www.kodak.com/global/en/professional/support/techPubs/e103cf/e103cf.pdf?id=0.1.20.14.18.14.7.14.16&lc=en

[Donald Qualls]

Assuming this is a rapid fixer formulation otherwise similar to the TF-2 formula given in Anchell & Troop, there should be plenty of sulfite present to preserve the thiosulfate and give shelf life similar to commercial acid rapid fixers -- minimum of three months at working strength, and as with Kodak, potentially indefinite if the steps are taken to exclude air.

I'd suggest trying it first the way you're used to, and doing clearing tests periodically to verify the fixer is still good. Some would suggest clearing time is a poor indicator of when the fixer will become difficult to wash out of the emulsion and especially paper, but it should work fine for tracking shelf life independent of capacity (you should, however, also track capacity to ensure you don't overuse your fixer).

[Doremus Scudder]

Here is the technical info from Photographers Formulary's TF-4. TF-3 should be similar.

STORING TF-4
All photographic solutions should be used as soon as possible. TF-4 stock solution should not be kept for more than 12 months. All fixers should be kept away from high heat (over 85° F), as this will shorten the shelf life. If TF-4 is to be kept for some weeks after opening, it should be placed in smaller bottles filled to the top, with tight caps.

For the complete tech sheet visit the site below and click on TF-4

http://www.photoformulary.com/DesktopDefault.aspx?tabindex=5&tabid=23

As for fixer that is already mixed: If you have been keeping it in a tightly stoppered, full bottle, it should last a week to a month, maybe longer. Do a clip test to make sure it is still active. If it fixes as fast, or almost as fast as fresh fixer, it is probably OK.

If you have not established clearing time for a particular film in fresh fixer, you do not have any base line to measure the older fixer against.

Good luck.