Testing TF-4

cbphoto · Dec 12, 2013

I have been printing with TF-4 this week in a slot processor (holds one gallon of fix), and wanted to know if a film clip test is accurate for paper fixer. My current batch cleared a film end in about 35-40 sec. Am I good, or is there a better way to test for paper fixer exhaustion? It's been a while

Thanks!

wildbill · Dec 12, 2013

(there was a url link here which no longer exists)
silver content test strips

for some fixers -http://www.freestylephoto.biz/69800-Arista-Premium-Hypo-Check-.75-oz.

bernard_L · Dec 12, 2013

Mix a small quantity of fresh fixer. Test film clip:
Immerse to 50%, wait 10s; immerse 100%, and count from beginning until uniformly clear.
Repeat with suspect fixer. Discard when clearing time is 2x new fixer.

If you don't have fresh fixer available here's my data:
- film fixer (1+4) fresh: 20-25s
- paper fixer (1+9) fresh: about double of above

cbphoto · Dec 12, 2013

Thanks. That's what I do, but I was not sure that that test was also valid for paper.

bdial · Dec 12, 2013

You need to do a residual silver test, which can be done with selenium toner. Info in this thread;
(there was a url link here which no longer exists)

Rudeofus · Dec 12, 2013

Or you rely on the fact that TF-4 was thoroughly tested by its inventors and just use the recommended times ...

Gerald C Koch · Dec 12, 2013

You can directly check the condition of the fixer by using Kodak Fixer Test Solution FT-1. Google the web for how to make it (it uses potassium iodide) and how to use it. Do not confuse this test with that for HT-1a. However the best way is to just keep track of the number of prints you put through the fixer and not exceed the recommended number of in3.

cbphoto · Jan 16, 2014

bdial said:
You need to do a residual silver test, which can be done with selenium toner. Info in this thread;
(there was a url link here which no longer exists)

So I just tried this on a washed print from last night, and no stain developed. I just used full strength KRST on a Q-Tip. If I wanted to test periodically throughout the day, is it possible to use a partially-washed print? It is terrible to go through all that trouble washing to find out something wasn't fixed all the way, especially since I print all day long and wash mostly at the end.

As an aside, my understanding is that KRST concentrate does not go bad. Mine is 3 years old in a half-full (or half-empty) bottle.

UPDATE: I just pulled a test print from the TF-4 and rinsed very superficially (filled and dumped quickly twice). I dabbed some straight KRST on a corner and dumped about a quarter of a capful in another corner. No stain at all. Either my fix is good and you can indeed test without thorough washing, or my KRST is dead.

Gerald C Koch · Jan 16, 2014

Rudeofus said:
Or you rely on the fact that TF-4 was thoroughly tested by its inventors

+1

It is so much simpler to just keep track of the number of in2 of paper processed and not exceed the amount stated for the fixer. The capacity of TF-4 is about 30 8x10 prints of fiber-based paper, 60 8x10 prints of resin coated paper, per liter of working solution. Trying to eek out any more prints is an unwise economy if archival permanence is important to you whether you test or not.

cbphoto · Jan 16, 2014

I think a chemical test would be easier and more reliable, no? I have a gallon standing for days in a Nova processor, and run various sizes through - some just odd-sized ripped up strips for testing - so calculation would be a bit complicated.

Gerald C Koch · Jan 16, 2014

The chemical test relies on a subjective decision by the user. Just how dark does the spot have to be to discard the fixer? Many years ago Kodak used to publish a darkroom handbook which gave a color chart that one could use with the test. Without this chart and test is quite iffy. BTW, the selenium toner was not used full strength for the test. I don't remember offhand the dilution that Kodak recommended for this selenium alternate test. The actual Kodak test calls for sodium sulfide. So the test using selenium may yield a different color and intensity.

Paul Glover · Jan 17, 2014

Gerald C Koch said:
+1

It is so much simpler to just keep track of the number of in2 of paper processed and not exceed the amount stated for the fixer. The capacity of TF-4 is about 30 8x10 prints of fiber-based paper, 60 8x10 prints of resin coated paper, per liter of working solution. Trying to eek out any more prints is an unwise economy if archival permanence is important to you whether you test or not.

I've taken to keeping a tally of sheets processed through the fixer after exhausting my first batch without realizing it because I hadn't kept track. Each RC 8x10 sheet is one "tick", FB 8x10 is two, double those for 11x14. When it hits 60 ticks, the liter of fixer gets replaced. I'm starting to do the same for film now too. It's not like I'm going to save a ton of money on fixer if I stretch it out by a couple more rolls of film or a half-dozen more sheets of paper.

I don't generally print smaller than 8x10 and am tending to be generous with my test strips as I move toward split grade printing, half a sheet for the soft test strip and the other half for the hard test strip. These factors do help simplify the tracking a lot.

Doremus Scudder · Jan 18, 2014

Paul Glover said:
I've taken to keeping a tally of sheets processed through the fixer after exhausting my first batch without realizing it because I hadn't kept track. Each RC 8x10 sheet is one "tick", FB 8x10 is two, double those for 11x14. When it hits 60 ticks, the liter of fixer gets replaced. I'm starting to do the same for film now too. It's not like I'm going to save a ton of money on fixer if I stretch it out by a couple more rolls of film or a half-dozen more sheets of paper.

I don't generally print smaller than 8x10 and am tending to be generous with my test strips as I move toward split grade printing, half a sheet for the soft test strip and the other half for the hard test strip. These factors do help simplify the tracking a lot.

What makes you think that RC paper has less silver halide in the emulsion than fiber-base paper? Fixing capacity should be roughly the same for both. It's washing time that is different between RC and fiber.

And, as long as we're on the topic... Use two-bath fixing if you're interested in permanence. Use the manufacturer's recommendation as a guideline and do your own residual silver testing on top of that.

Best,

Doremus

www.DoremusScudder.com

Xmas · Jan 18, 2014

Doremus Scudder said:
What makes you think that RC paper has less silver halide in the emulsion than fiber-base paper? Fixing capacity should be roughly the same for both. It's washing time that is different between RC and fiber.

And, as long as we're on the topic... Use two-bath fixing if you're interested in permanence. Use the manufacturer's recommendation as a guideline and do your own residual silver testing on top of that.

Best,

Doremus

www.DoremusScudder.com

^
^
^
Or even and as well if/when bath A slows detectably replace it with bath B and make a new bath B. taking a risk with fix is not good, especially with paper. Plain hypo is not that expensive compared with paper?

cbphoto · Jan 18, 2014

Doremus Scudder said:
Use the manufacturer's recommendation as a guideline and do your own residual silver testing on top of that.

That's why I'm asking. I do have a rough idea of my throughput per batch (without exactly calculating), but would like to be able to physically verify. And since I have KRST on hand...

Gerald C Koch · Jan 18, 2014

I you insist on testing then you will need the following book as it contains the chart to compare your result. Otherwise you will not really have a good idea of when the fixer is still good. Still useable fixer will leave a stain, it is the depth of the color that makes the difference. The book also details how to do the test. IIRC the rapid selenium toner is diluted 1+9 for the test, using it FS will give a false reading.

http://www.amazon.com/Kodak-Black-D...qid=1390090194&sr=8-3&keywords=kodak+darkroom

Doremus Scudder · Jan 19, 2014

Here is the Kodak info on using selenium toner as a text for adequate fixation.

Mix:
Kodak Rapid Selenium Toner...10 milliliters Water to make...............100 milliliters (1+9)
1. Use a print that has been processed in the suspected fixer.
2. Place a drop of the diluted solution on a squeegeed, white margin of the print (or a clear part of film).
3. Wait three minutes; then wipe off the drop with a clean blotter or cloth. If the test leaves any discoloration other than a slight cream tint, the fixer is exhausted.

More info from (there was a url link here which no longer exists)

The poster there maintains that KRST full-strength works as well as the more common sulfide test and that KRST diluted 1+9 is only slightly less sensitive.

FWIW, I think that the selenium method is likely good. I tone all of my prints in selenium anyway, so I have a "built-in" residual silver test. Nonetheless, I still regularly use the sulfide test for residual silver as well just as a check.

@Gerald: I'm not sure the chart for the HT-2 residual hypo test is applicable to using selenium toner for a residual silver test... Is there another comparison chart that I'm not aware of?

Best,

Doremus

cbphoto · Jan 19, 2014

Thanks, both. I read that thread, but I wasn't clear on whether or not the print has to be washed all the way. If it does, that's obviously a lot of time and water down the drain.

RalphLambrecht · Jan 19, 2014

I agree with Gerald. use the two-bath fixing method and keep a count of the sheetsand you'll be fine.residual fixer tests are very subjectivebut give indicationwhen gone too far already.

RalphLambrecht · Jan 19, 2014

cbphoto said:
Thanks. That's what I do, but I was not sure that that test was also valid for paper.

it is. itis.

RalphLambrecht · Jan 19, 2014

cbphoto said:
Thanks. That's what I do, but I was not sure that that test was also valid for paper.

it is. it is.

RalphLambrecht · Jan 19, 2014

Gerald C Koch said:
You can directly check the condition of the fixer by using Kodak Fixer Test Solution FT-1. Google the web for how to make it (it uses potassium iodide) and how to use it. Do not confuse this test with that for HT-1a. However the best way is to just keep track of the number of prints you put through the fixer and not exceed the recommended number of in3.

warning.the potassium iodide test is inadequate.by the time it signals fixer exhaustion,your fixer contains above 2gof silver/liter,which is way above the limit for 'archival'use, but with two-bath fixing, you can use it to test if it is time to replace the first bath. remember to always follow up with a fresh second bath.

cbphoto · Jan 19, 2014

RalphLambrecht said:
it is. it is.

That's good news!

cbphoto · Jan 19, 2014

RalphLambrecht said:
I agree with Gerald. use the two-bath fixing method and keep a count of the sheetsand you'll be fine.residual fixer tests are very subjectivebut give indicationwhen gone too far already.

I'd like to use a two-bath fix, but my Nova slot machine only has three slots. My understanding is that stop is safe with TF-4, so that's in the middle. If I find room to set up trays someday, I'll use two.

Doremus Scudder · Jan 20, 2014

cbphoto said:
I'd like to use a two-bath fix, but my Nova slot machine only has three slots. My understanding is that stop is safe with TF-4, so that's in the middle. If I find room to set up trays someday, I'll use two.

How do you tone? Certainly not in the Nova, do you? If you are toning in a tray, then it is really easy to just set up another tray of fix. Fix in the second fix and then transfer directly to the toner. I usually print, wash and dry my prints and tone everything later in a separate toning session. My trays for toning are: water pre-soak, fixer 2, toner, hypo-clear, then directly into the washer.

Hope this helps a bit.

Doremus

Testing TF-4

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