Had some discussions here about fix testing - I've been using straight hypo for bromoil tests (some claim easier inking vs. rapid) and for Lith (to prevent highlight bleaching). I've been buying small jars of sodium thiosulfate for testing and will order 5 or 10 pounds next time - I've not added sodium sulfite thus far. Small batches of thiosulfate means I've not had a lot of chemistry around.
So after making a round of matrices and fixing post-bleach, I bottled up the plain fixer thinking I might do some more prints that night. Last night - a week or two later - I was playing with Lith and noticed I still had that used fixer and trayed it, but I assumed it was dead without the sulfite.
Some folks on APUG use the film leader test to determine fixer life, others say film-leader doesn't address the differences between fixing paper and film. I just took a strip of paper in room light, bent it so half hung in the fix tray, tested two and three minute strips, and dropped into a graduate with Liquidol (Dektol) 1:9, my standard paper soup. The unfixed halves went straight black, the fixed halves pure white. Even 2 minutes in plain hypo left the paper totally white, so I settled on 3 minutes fixing time. I tested every 3 or 4 prints and the stuff was still good.
I was just using single-bath fixing as well... all I had new was rapid fix, these were just tests, and (I'm assuming) the single bath was doing what it was intended to do, remove the unneeded silver.
Now, my brain clouds up and eyes glaze over when people start saying "well, the silver halides are transmorgified into gluten strands which your test does not address" (love you chemists, but my brain is just full these days I guess). Beyond the science involved, I'm assuming the paper strip test tells me the stuff is doing its job (yet everything I've read says that particular fix batch should be dead by now).
Is my methodology sound and are my assumptions correct? I would be very happy to have such a simple way to determine whether new fix is needed.
So after making a round of matrices and fixing post-bleach, I bottled up the plain fixer thinking I might do some more prints that night. Last night - a week or two later - I was playing with Lith and noticed I still had that used fixer and trayed it, but I assumed it was dead without the sulfite.
Some folks on APUG use the film leader test to determine fixer life, others say film-leader doesn't address the differences between fixing paper and film. I just took a strip of paper in room light, bent it so half hung in the fix tray, tested two and three minute strips, and dropped into a graduate with Liquidol (Dektol) 1:9, my standard paper soup. The unfixed halves went straight black, the fixed halves pure white. Even 2 minutes in plain hypo left the paper totally white, so I settled on 3 minutes fixing time. I tested every 3 or 4 prints and the stuff was still good.
I was just using single-bath fixing as well... all I had new was rapid fix, these were just tests, and (I'm assuming) the single bath was doing what it was intended to do, remove the unneeded silver.
Now, my brain clouds up and eyes glaze over when people start saying "well, the silver halides are transmorgified into gluten strands which your test does not address" (love you chemists, but my brain is just full these days I guess). Beyond the science involved, I'm assuming the paper strip test tells me the stuff is doing its job (yet everything I've read says that particular fix batch should be dead by now).
Is my methodology sound and are my assumptions correct? I would be very happy to have such a simple way to determine whether new fix is needed.
