recycling fix

[Tom Hoskinson]

Using Hypo Chek is a good method, but you should draw off a sample to use for the test and discard afterward, as it will weaken the fix otherwise. (search should show up PE's comments on this).
With film I check the film at 1/2 the minimum time stated on the fixer's data sheet. If the film is clear (usually) then I simply fix for the minimum stated time. Otherwise I double the clearing time, up to the max stated on the data sheet. That is, the clearing time should never exceed the 1/2 max time stated in the data sheet.

It's wasteful and polluting to dump the fixer after one use, either for film or paper, after all, you are dumping heavy metals (silver) into the waste stream. Or in my case with a septic system, into ground water that I might eventually drink. Thanks but no thanks.

Yup! That's why I recycle fix and don't dump it.

[Neanderman]

Using Hypo Chek is a good method, but you should draw off a sample to use for the test and discard afterward, as it will weaken the fix otherwise. (search should show up PE's comments on this).

Again, it's the iodide that is used in hypo check.

Ed

[Tom Hoskinson]

In my lab (at work) we still wet process a lot of Xray film and Kodak Tech Pan (we have freezer full of Tech Pan). We send all of our used fixer to a silver recovery sevice.

[BobNewYork]

Even though I use the same fixer and dilution for film and paper I've never mixed them - not for any particular reason, I just haven't. reading Tom's post, I'm glad I didn't now. (I'd rather be lucky than good!)

My largest film tank takes 1.5 litres of solution so I keep a one litre and a half litre on hand. In use, I pour in fixer from the litre bottle and at the end return it to top off the half litre, pouring the balance into the"ex-litre" bottle. This way the entire one and a half litres gets the same usage. A while back, I ran tests with a single litre - clearing times and hypo check and found that the clearing time doubled after 21 films. On this basis I fix 20 films in my litre and a half before replacing the batch.

[jp80874]

It's wasteful and polluting to dump the fixer after one use, either for film or paper, after all, you are dumping heavy metals (silver) into the waste stream. Or in my case with a septic system, into ground water that I might eventually drink. Thanks but no thanks.

bdial,

Assuming that comment was for me, the dump after one use is in the Rollo Pyro manufacturer's (Bostick & Sullivan) instructions. The same instructions say use only 350ml of fixer for five sheets of 8x10. At this point the fixer is also heavily loaded with pyro stain that would do nothing positive for fixing prints of snow scenes. "Dump" in my case, means dump the 350ml plus the first two 450ml rinses of the Jobo Expert tank into a gallon jug. When I accumulate three or four gallons, I take them to the University where I still take courses at age 67. The University encourages students with home darkrooms to use the school's silver recovery system to "help save the environment". I also have a well upstream from our septic system.

John Powers