Selenium toner as fixer test?

Jeff Bannow · Oct 18, 2010

Currently using TF-4 without a stop bath, may move to using a stop bath soon.

I believe I read at some point that you could use a bit of selenium toner dropped onto a print in the white margin as a test for proper paper fixation. Anyone know about this? Is my memory finally failing me? Would this somehow work for film as well?

I need to start regularly testing and this seems a good way to go, since it lasts forever and I already keep it in the darkroom.

Otherwise, suggested alternatives?

Bruce Osgood · Oct 18, 2010

This is my understanding as well. I can't recall where I got it either but it may have been from Richard Knoppow at PureSilver. I have not heard it regarding film though.

nworth · Oct 18, 2010

The usual fixing test involves a sodium sulfide solution. Selenium toners are somewhat similar. Because most common selenium toners are the single bath variety, they may contain additional ingredients that could affect the sensitivity of the tests. The most common such ingredient in published formulas is ammonium chloride, but I have no idea what something like KRST contains.

Residual silver test
Water 60 ml
Sodium sulfide 7.5 g
WTM 100 ml
Place a drop in a clear area of a print (border). Wait 5 minutes. A brown stain indicates the presence of silver and insufficient fixing.

Anon Ymous · Oct 19, 2010

Yes, KRST will stain a partially fixed paper/film. The usual dilution, although not critical, is 1+9. Just place a drop at the border and leave it there for 2-3'. KRST (and perhaps all off the shelf selenium toners) contain ammonium thiosulphate. If you place a drop of it on cleared, but unfixed film, you'll notice that it will fix it a bit more, but it'll also stain it, it's quite obvious. The advantages of using KRST, instead of sodium sulfide are:

1) You probably already have it on your shelf.
2) The solution has a very, very long life, as opposed to Na2S.

The typical Na2S test solution (ST1) is 2g of Na2S in 125 ml of water. This is stock and its further diluted 1+9 to perform a test. Kodak recommends keeping the stock for no more than 3 months and the working (1+9) solution for a week. The drop is left for 2-3' in this case too, but it doesn't have any fixing action, just staining. It will turn any left halides to silver sulfide, just like a typical sepia toner. Anything more than a barely visible stain indicates partial fixation.

Both methods appear in Kodak's technical publication J1.

Dan Henderson · Oct 19, 2010

Jeff: why are you considering using a stop bath (instead of, I presume, water?) With the exception of lith prints that must be stopped immediately, I have not used acid stop bath since I began using TF4 and 5 several years ago. Even when I lith print I rinse the print in water for 30 seconds between the stop bath and fixer. This might be just bottle rocket science, but the water rinse seems like a good buffer between the acid stop and alkali fixer, plus I figured the fixer would last longer and work better without the contamination of the stop bath.

Jeff Bannow · Oct 19, 2010

Thanks everyone - sounds like just the info I needed.

Anyone recommend a good wash test along the same lines?

Dan - right now I'm just filling a tray with water and agitating between dev and fix. I change the water when I think of it - not the ideal setup. I guess I don't have a good way to keep water running in the tray when I have large groups in the darkroom. Does anyone make a tray that connects to the faucet? That might be ideal.

So, it seemed that an acid stop would be a solution. Ron Mowrey / Photo Engineer indicated that TF4 could handle it, but I haven't researched it too much yet.

George Collier · Oct 19, 2010

Hey Jeff - I can't believe you asked that question yesterday about the Selenium as a test for fixing - I was doing a semi stand development last night, and during the waiting periods, I was perusing an old (like from the 70's) Kodak Darkroom Guide. (I still use the developing and enlarging wheels.)
There was a section in the back about this kind of stuff, and it stated that a dilution of 1:9 of KRST could be used as a fix completion test. I don't have the book with me at the moment, but I believe you put a drop on the white border area and see if it stains. I'll re-post tonight if my memory is off (well, about this, anyway...)

Jeff Bannow · Oct 19, 2010

Thanks George - that's what I thought it was.

Dan Henderson · Oct 19, 2010

Jeff: when I first set up my darkroom I used a Premier Rapid Print Washer. It has a hose that connects to the faucet and some distribution holes in that end, and some exit holes at the opposite end. I probably bought it from B&H or Calumet. You can adjust the water flow so just a trickle goes through.

I still use it once in awhile if I have just a couple of 11x14 prints and don't want to fill up my big washer or I would offer it to you.
Dan

Jeff Bannow · Oct 19, 2010

Dan Henderson said:
Jeff: when I first set up my darkroom I used a Premier Rapid Print Washer. It has a hose that connects to the faucet and some distribution holes in that end, and some exit holes at the opposite end. I probably bought it from B&H or Calumet. You can adjust the water flow so just a trickle goes through.

I still use it once in awhile if I have just a couple of 11x14 prints and don't want to fill up my big washer or I would offer it to you.
Dan

Thanks for the tip Dan - you mean one of these?

http://www.freestylephoto.biz/111411-Premier-Print-Washer-11x14?cat_id=1604

So if I set that to trickle out I'd be good to go. That looks perfect.

Dan Henderson · Oct 19, 2010

Jeff Bannow said:
Thanks for the tip Dan - you mean one of these?

http://www.freestylephoto.biz/111411-Premier-Print-Washer-11x14?cat_id=1604

So if I set that to trickle out I'd be good to go. That looks perfect.

Jeff: that is the one. Yep, you can regulate the water throughput to as meager of a trickle as you want.

Vlad Soare · Oct 20, 2010

Tim Rudman mentions this test in his toning book. I've tried it myself, putting a drop of full strength selenium toner (Moersch MT1, not KRST, in case it matters) on the white border of a well washed print, as well as on the white border of a test strip that I hadn't bothered to wash too well.
On the test strip it left a definite brown stain in less than two minutes.
On the well washed print it didn't leave any mark. After almost ten minutes not even the faintest trace of a stain was visible.

2) The solution has a very, very long life, as opposed to Na2S.

My sepia toner, which is a simple 1% sodium sulfide solution, is still working normally after six months and tens of prints. I just filter that blue scum from time to time. It may not last as long as full strength selenium toner, but it's not so short-lived either.
The only unpleasant thing about sodium sulfide is that the moment you open the bottle it stinks up the entire room. But on the other hand, so does the selenium toner. I think I hate its ammonia smell even more than the smell of hydrogen sulfide.

clayne · Oct 20, 2010

Se toner isn't even close to the stench of any sulfide toner. Not by a long shot.

You can barely even smell 1+20 solutions. 1+10 is only slightly there.

Vlad Soare · Oct 20, 2010

It may depend on the specific formula. I've never used KRST. My only experience is with Rollei and Moersch. The Rollei toner doesn't smell at all, not even in concentrated form. It's totally odorless.
Moersch MT1, on the other hand, has a strong and prickly ammonia smell, even at 1+30. As for the concentrate, when I open the bottle the smell is so strong that it feels almost like a blow.

clayne · Oct 20, 2010

Sure, but so is the smell of stop bath (acetic acid). Smell that and you'll be on the floor. None of these solutions are used regularly at full strength by any means.

On the flip-side Sulfide toners are typically very low odor in concentrated form - but when they combine with water, someone just took a crap in the darkroom.

Vlad Soare · Oct 20, 2010

Sure, but so is the smell of stop bath (acetic acid).

Yup. That's why I'm using citric acid instead.

On the flip-side Sulfide toners are typically very low odor in concentrated form - but when they combine with water, someone just took a crap in the darkroom.

Indeed, I've noticed that, too. The smell gets noticeably worse when I place the toned prints in the water tray and start washing them.
I don't know... If we could somehow measure the level of stink, then who knows, maybe hydrogen sulfide would rank much higher than ammonia. But personally I just happen to find the "prickliness" (is that a word?) of ammonia smell much more disagreeable than the foul smell of hydrogen sulfide. I don't know how to express this; it's like hydrogen sulfide annoys me, while ammonia feels almost painful. But that may be just a personal thing...

Jeff Bannow · Oct 20, 2010

Thanks for the info everyone.

nworth · Nov 1, 2010

I was curious about the sensitivity of using KRST as a residual silver test, so I did some tests to compare it to the more usual sodium sulfide test. I cut several test strips from a sheet of Ilford Multigrade IV FB paper and fixed each in fresh Kodak F-24 non-hardening fixer with continuous agitation for 1, 2, 3, 4, an 5 minutes respectively. After fixing, I rinsed each strip thoroughly in running water. I rinsed a sixth strip without fixing it as well. The F-24 took a little over 4 minutes to clear a piece of fogged film. I estimated that that would also be about the full fixing time for paper. Kodak recommends 5-10 minutes for similar sodium thiosulfate fixers. I arranged the fixed test strips in the bottom of a dry tray and placed one drop each of a 7.5 percent solution of sodium sulfide, undiluted KRST, and KRST diluted 1+9. After three minutes I rinsed all the test strips and examined them. Undiluted KRST proved to be about as sensitive as sodium sulfide, and KRST diluted 1+9 was only slightly less sensitive. The test showed a slight brown tone for the 4 minute strip, and essentially no reaction on the 5 minute strip. Other strips were strongly colored. I do not have the equipment and supplies to do the ISO standard test for residual silver in papers, so I can not tell if the 5 minute strip was fixed to anywhere near archival standards. But as a comparison, I can say that KRST seems to work as well as sodium sulfide as a residual silver test.

Jeff Bannow · Nov 2, 2010

Thanks for that update - very useful information. Definitely helps to have one less chemical solution to store in the darkroom.

clayne · Nov 3, 2010

True, although Selenium is a given to have in the darkroom for general post-toning and Sodium Sulfide is sepia toner so I'd think they're all required if you want to do more than just simple printing.

Selenium toner as fixer test?

Membership Council

Privacy & Transparency

Privacy & Transparency