Sodium Sulfite as hypo clear?

I’ve been mixing a few spoons of sodium sulfite into my print holding tray water. I let prints sit there until I’m done. I then was them in a print washer for an hour.
Is that enough?

Also, fixing paper is this an OK test?
I rip a test strip into four pieces with the lights on. I then fix the pieces for 15s, 30s, 45s and 1m. Wash them and drop them into the developer tray. After two minutes I can still see a faint shadow on the 45s piece. The 1min looks clean white.
Is my fixer about to die?

This is fiber paper in acetic fixer.

If you wash photographic paper after fixation, you initially remove thiosulfate through diffusion. This will get rid of most of the thiosulfate in your paper very quickly, but not of enough to ensure archival stability. After that initial diffusion process, the paper enters a slow process of ion exchange, where thiosulfate ions are slowly replaced with ions dissolved in your wash water. This second stage of thiosulfate removal works very slowly in deionized water, somewhat faster in normal tap water, and quite fast in water with extra ions. Sea water is fast, water with sodium carbonate is fast, and water with sodium sulfite is the fastest.

However, and this is where my explanation becomes relevant to your original question: this addition of Sodium Sulfite only benefits stage 2, it offers nothing for the initial diffusion stage. As you put more and more freshly fixed paper into your holding tray, you will bring more and more thiosulfate into that wash water, and residual thiosulfate levels will remain above the limit, where significant ion exchange would take place. If you then throw this pre-rinsed paper into your regular wash water, you are in pretty much the same situation as if you would have omitted the Sodium Sulfite from the onset. The only benefit from your Sodium Sulfite bath would be, that the sulfite raises pH - so your paper should wash as fast as if you would have used neutral or alkaline fixer. You might as well use baking soda, if that's cheaper.

PS: what's the reason for using acidic fixer, especially if washing speed is of concern?

ericdan said:

I’ve been mixing a few spoons of sodium sulfite into my print holding tray water. I let prints sit there until I’m done. I then was them in a print washer for an hour. Is that enough?

Also, fixing paper is this an OK test?
I rip a test strip into four pieces with the lights on. I then fix the pieces for 15s, 30s, 45s and 1m. Wash them and drop them into the developer tray. After two minutes I can still see a faint shadow on the 45s piece. The 1min looks clean white. Is my fixer about to die?

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You could be a bit more precise with your measurements here... Still, 1 Tablespoon of sodium sulfite per liter is close enough. Add a pinch of sodium metabisulfite (or bisulfite) if you have it around to adjust the pH a bit and make for more efficient ion exchange.

As Rudi points out above, you should at least rinse your prints before putting them in the wash-aid tray. A better work flow is to have a tray with running water (I have a tray with a row of holes drilled in one end and I just trickle water into the other). Prints can go there for a few minutes and then into the wash-aid tray. If you don't rinse, the capacity of your wash-aid is greatly reduced by the build-up of carried-over fixer. Kodak's Hypo Clearing Agent's capacity without a pre-rinse is 12-15 8x10s per liter. If you don't rinse, do keep an eye on capacity.

Washing for an hour should be alright, but you can and should test. Read up on the HT-2 residual hypo test. It's easy and quick and will give you peace of mind.

As for testing fixer: I've found no better way than testing prints for residual silver. The problem with strip tests, like you do, and Hypo-Check solutions is that they aren't sensitive enough for archival processing of fiber-base prints. A two-bath fixing regime and using the manufacturer's throughput recommendations is a good start. Then test your workflow by testing the last print through both fixing baths (after washing). You can use the Kodak or Formulary ST-1 residual silver test, or (my preference) you can use Kodak Rapid Selenium Toner diluted 1+9. Place a drop on the clear border of the print, wait 3 minutes and rinse off. Anything other than a very faint cream color is indicative of inadequate washing.

By the way, the strip test you describe just tells you what the clearing time is for the fixer and paper you are using. The clearing time in fresh fix will be less than that in partially used fix. You could do a lot of testing by comparing clearing times in fresh and partially used fixer along with the residual silver test as a control of when the fixer needs to be discarded, then figure in a safety margin and come up with some kind of clearing time limit that would work for that particular fixer and paper. Seems like a lot of work to me. Really, the best method is to use two-bath fixing, the manufacturer's throughput recommendations and do the drop test.

Hope this helps,

Doremus

Rudeofus said:

If you wash photographic paper after fixation, you initially remove thiosulfate through diffusion. This will get rid of most of the thiosulfate in your paper very quickly, but not of enough to ensure archival stability. After that initial diffusion process, the paper enters a slow process of ion exchange, where thiosulfate ions are slowly replaced with ions dissolved in your wash water. This second stage of thiosulfate removal works very slowly in deionized water, somewhat faster in normal tap water, and quite fast in water with extra ions. Sea water is fast, water with sodium carbonate is fast, and water with sodium sulfite is the fastest.

However, and this is where my explanation becomes relevant to your original question: this addition of Sodium Sulfite only benefits stage 2, it offers nothing for the initial diffusion stage. As you put more and more freshly fixed paper into your holding tray, you will bring more and more thiosulfate into that wash water, and residual thiosulfate levels will remain above the limit, where significant ion exchange would take place. If you then throw this pre-rinsed paper into your regular wash water, you are in pretty much the same situation as if you would have omitted the Sodium Sulfite from the onset. The only benefit from your Sodium Sulfite bath would be, that the sulfite raises pH - so your paper should wash as fast as if you would have used neutral or alkaline fixer. You might as well use baking soda, if that's cheaper.

PS: what's the reason for using acidic fixer, especially if washing speed is of concern?

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Thanks for the explanation. I have sodium sulfate sitting around and thought I’d put it to use. Once it’s gone I could switch to baking soda.
I’m using Adofix for no particular reason. It’s slightly acidic.

Is there a chance, that you can leave the paper under running water just for a few minutes before you place it into the holding tray with sulfite? That initial washing stage, in which diffusion dominates, doesn't usually take very long, and you could really cut down the final washing stage.

ericdan said:

I have sodium sulfate sitting around and thought I’d put it to use.

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Sulfate, or sulfite? The discussion and useful suggestions of @Rudeofus assume sulfite, not sulfate. They are NOT interchangeable.

I happen to have a closely related question; close enough that I believe I'm not hijacking the thread.
My normal process is (beyond final fix, whether single or second)

• holding tray with water, renewed and stirred at scarce intervals
• sulfite 10g/L 5 min
• washing, with aquarium pump for circulation, two changes of water (three baths) 10min each
• photo flo 1cc/1L 1min

My question:
Can I merge sulfite bath with first wash? That seems to mesh with post #3 by rudeofus. Arguments, please, not opinion or authority.

Bernard,

Are you speaking of prints or film? The photo-flo step makes me believe you're referring to film. In any case, you're better off rinsing your film or print for a few minutes before the wash-aid step. That said, if you use your wash-aid to a lower capacity (see my post above), you can transfer directly from the fix to the wash aid. Kodak says for its Hypo Clearing Agent that with a water rinse between fix and wash aid increases capacity fourfold, to 200 8x10s per gallon. Without the rinse the capacity is only 50-60 8x10s per gallon (read 50 8x10s per liter vs. 12-15 8x10s per liter).

Bottom line, what you're doing now is better than no rinse at all. A running water rinse for a few minutes would be even better. Whatever you decide to do, keep an eye on your capacity.

Best,

Doremus

Doremus Scudder said:

Are you speaking of prints or film?

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Doremus, that is for prints. I should have been explicit. For films, I use the Ilford washing sequence, much shorter (no hypo-laden paper base!).

Doremus Scudder said:

That said, if you use your wash-aid to a lower capacity (see my post above), you can transfer directly from the fix to the wash aid.

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The capacity question does not arise, because printing is a slow process, for me at least. And I might keep the sulfite solution for two consecutive days, but not much longer. Anyway, I do a rinse before the sulfite.

My specific question was: in order to save time (and one tray), can I go from the rinse to the first 10-minute wash, and trow into that a spoonful (spoon needs to be calibrated) of sulfite? I would typically dump (at the end of the first 10-min wash) one spoonful of sulfite every half-day (when I do final processing of accumulated prints), the price to pay for merging two steps and saving the room for the sulfite tray.

Bernard,

You must be using the Ilford wash sequence for your fiber-base prints (or should I say, "fibre"?)

They call for a five-minute running-water wash after fixing, then 10 minutes in their wash aid and then a final running-water 30-minute wash. This is a good sequence as long as the fix is strong, the fixing times are kept short (1 minute, tops) and the capacity of the fix is not exceeded.

I find that keeping the fixing time to just one minute is troublesome, especially with larger prints or when I'm bleaching and have to return the print to the fixer, so I use the old tried and true Kodak method (which saves the tray space you seem to need...)

I use two-bath fixation, since the single-bath capacity for optimum permanence is so low as to be really uneconomical (only 10 8x10s per liter of fix - I can do 35-40 8x10s through two liters of fixer with the two-bath method; and then move the second bath to position one for the next batch...).

Anyway, my work flow, which might be of use to you, is: Develop, Stop, Fix 1 (optional wash and dry, then resoak), Fix 2, Selenium Toner, Wash Aid (note, I don't use a rinse between the toner and the wash aid, but I do adjust my capacity accordingly; 20 8x10s per liter maximum), Wash (60 minutes minimum in running water).

In other words, you don't need a wash step before the wash aid. If you are rinsing your prints, say, in a running water tray for a few minutes, you can transfer them directly to the wash aid and then from there to the wash. I wouldn't add sulfite to the print washer for a number of reasons, mostly because I want my washer to be for washing; not to contain any chemical baths, but also because I couldn't control the concentration of the sulfite in a print washer that has a constant flow of water through it.

If you're not washing with running water, you need to fill and dump trays a lot. If that's what you're doing, then you could mix in your wash aid at some point after the first dump or two (don't mix it on top of prints, though!).

Hope that helps,

Doremus

Doremus,
Thank you for your detailed reply. Just a few clarifications.

Doremus Scudder said:

You must be using the Ilford wash sequence for your fiber-base prints (or should I say, "fibre"?)

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When I mentioned the Ilford wash sequence

bernard_L said:

For films, I use the Ilford washing sequence

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Mentioned there: https://www.ilfordphoto.com/wp/wp-content/uploads/2017/03/Reducing-Wash-Water.pdf, specifically:
I actually do 10-20-30 just because. And I tested with a drop of HT-2 on clear film.

Now returning to paper. The sequence that you describe presumably (I write "presumably" just because I have no personal experience, not as an expression of doubt) provides maximal permanence. My standard is not so high.

Doremus Scudder said:

you need to fill and dump trays a lot.

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Not a lot. As I wrote in my first post #8 above, two changes, i.e. three baths, each 10min with constant circulation. And, then again, that is after initial rinse/hold ans then sulfite. I tested with HT-2; spot hardly visible after the second bath, so the third bath is just for the margin of safety.

Doremus Scudder said:

Anyway, my work flow, which might be of use to you, is: Develop, Stop, Fix 1 (optional wash and dry, then resoak), Fix 2, Selenium Toner, Wash Aid

Click to expand...

Can you really go from Fix 2 directly into Selenium Toner, even if Fix 1 is loaded with silver (which it will be after 40 prints, and some of that silver will inevitable carry over to Fix 2) ?

Rudeofus said:

Can you really go from Fix 2 directly into Selenium Toner, even if Fix 1 is loaded with silver (which it will be after 40 prints, and some of that silver will inevitable carry over to Fix 2) ?

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IIRC, you can, but this affects the selenium toner solution and reduces it's life drastically. The toner itself contains quite a bit of ammonium thiosulfate.

It is generally a good idea to do a proper wash between fixer and selenium toner.

Anon Ymous said:

IIRC, you can, but this affects the selenium toner solution and reduces it's life drastically. The toner itself contains quite a bit of ammonium thiosulfate.

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I am not so much concerned about carryover of thiosulfate, but about silver carryover. If there is any amount of Silver Thiosulfate left in the paper, Selenium Toner will react with it. AFAIK that's how test kits for retained silver ions work. If there is enough silver in Fix 1, some will carry over into Fix 2, and will be in the print after leaving Fix 2.

Rudeofus said:

I am not so much concerned about carryover of thiosulfate, but about silver carryover. If there is any amount of Silver Thiosulfate left in the paper, Selenium Toner will react with it. AFAIK that's how test kits for retained silver ions work. If there is enough silver in Fix 1, some will carry over into Fix 2, and will be in the print after leaving Fix 2.

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So, the dissolved silver thiosulfate will form silver selenide, thus drastically reducing toner capacity?

Anon Ymous said:

So, the dissolved silver thiosulfate will form silver selenide, thus drastically reducing toner capacity?

Click to expand...

I have the impression that this indeed does happen. I had a large bottle of used selenium toner which went red-brown over the course of a few weeks, suggesting that the selenium went out of solution. Either as a result of a redox reaction not involving any silver, or as a result of combination with silver in solution causing silver selenide to precipitate out. This rendered the toner completely ineffective and I had to dispose of it.

Doremus Scudder said:

...Then test your workflow by testing the last print through both fixing baths (after washing). You can use the Kodak or Formulary ST-1 residual silver test, or (my preference) you can use Kodak Rapid Selenium Toner diluted 1+9. Place a drop on the clear border of the print, wait 3 minutes and rinse off. Anything other than a very faint cream color is indicative of inadequate washing.\

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Caught a typo here - "Anything other than a very faint cream color is indicative of inadequate washing" - should be inadequate fixing, as you're testing for residual silver, not residual thiosulphate!

I just put a drop of straight selenium toner on my prints, after the initial rinse and before going to HCA. After all, there's thiosulphate in the selenium toner, and I don't want to go through the wash process and find I didn't fix enough. Is there a reason to wait til washing is complete to test for silver?

Also, surprised nobody's mentioned warm water for washing prints. Since diffusion is a chemical process, heat speeds it up. If your paper can handle a warm wash, it will definitely speed your wash and save some time/water (at least in my testing). I can get fiber paper clean (tested with Formulary's RHT) in about 20 minutes. FWIW, here's my process:

2-bath fixing (nobody's mentioned when to decide that bath 2 becomes bath one - for me it's when the strip in fresh fixer test hits 45 seconds or so. I generally test at the start of a session, and maybe halfway through if I'm doing a lot of prints, or there's a lot of high-key fixing going on). A solid initial rinse, print in a tray, at least one change of water, then all prints in a holding bath.

HCA (about a half film vial of Sodium Sulfite to a liter of water). I put about 200ML of very hot water in the graduate to get the powder dissolving, and then top it off from a jug of 1.5% salt water (1/4 cup of canning salt to 1 gallon). 2 minutes of HCA and then into the wash. Often I add a splash of the salt water to the initial wash stage, too (recall reading in one of Rudman's books that "almost anything" speeds the ion exchange, I guess I'm just making my own sea water? may be a waste of time, but it's fairly meaningless time and money to have salt water on hand). A running trickle-wash, pretty warm water, prints separated either in a large tray with bits of PVC pipe on end to keep them apart, or cascading trays - I even have a cascading tray set for 20x24 prints in the bathtub, with a hose running from the shower head - yeah, I need a print washer). After 15 minutes, slowly adjust the water to cold (to harden the paper's emulsion for final handling). Start testing borders after 20 minutes with RHT. Nice clean prints.

When I coat papers with liquid emulsion (for bromoil), it's all cold water though - I don't use a hardener and that stuff is delicate... I swear if you look at it too hard it'll scratch.

Rudeofus said:

Can you really go from Fix 2 directly into Selenium Toner, even if Fix 1 is loaded with silver (which it will be after 40 prints, and some of that silver will inevitable carry over to Fix 2) ?

Click to expand...

Rudeofus said:

I am not so much concerned about carryover of thiosulfate, but about silver carryover. If there is any amount of Silver Thiosulfate left in the paper, Selenium Toner will react with it. AFAIK that's how test kits for retained silver ions work. If there is enough silver in Fix 1, some will carry over into Fix 2, and will be in the print after leaving Fix 2.

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Hi Rudi,

There's no problem transferring prints directly from fix 2 to the toner as long as the prints are completely fixed and the fixer is not too acidic. I learned this from Ansel Adams and have been doing it for 30+ years with no ill effects whatsoever. It's not the completely converted (fixed) thiosulfate compounds that cause the staining apparently, but the unconverted silver or partially converted compounds. Hence Kodak's advice to use KRST as a test for residual silver.

The problems some have with stains and selenium toner all seem to be traceable back to either inadequate fixation or a too-acidic fixer. I use Hypam or Rapid Fixer 1+9, with a pH of about 5.0-5-5 (according to Ilford) and have no problems.

And, as you know, I replenish and reuse my toner indefinitely. Whatever silver compounds get carried over to the toner from fix 2 seems to precipitate out as a fine black precipitate and gets filtered out before and after each toning session. Because the precipitate is black, I surmise that it has not reacted with the selenium, at least not in the same toning reaction. I don't understand exactly what's happening though. I just toned a batch of prints in 10+-year-old toner a couple of days ago. It works just fine.

The last print through fix 2 before I promote it to fix 1 (or downgrade it, I guess) gets tested after the wash for both residual silver and hypo. Always zero stain.

Best,

Doremus

bernard_L said:

Doremus, Thank you for your detailed reply. Just a few clarifications...

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Sorry if I addressed the wrong thing here; since the original post was about prints, I was fixated on them

Doremus

Anon Ymous said:

IIRC, you can, but this affects the selenium toner solution and reduces it's life drastically. The toner itself contains quite a bit of ammonium thiosulfate. It is generally a good idea to do a proper wash between fixer and selenium toner.

Click to expand...

Anon Ymous said:

So, the dissolved silver thiosulfate will form silver selenide, thus drastically reducing toner capacity?

Click to expand...

See my above post to Rudi. Two things, though: I have not found that washing thoroughly before toning to reduce the life of the toner "drastically." I'm sure it gets reduced a bit, since it has to react with the small amount of silver compounds carried over with the fix (the black precipitate in my replenished toner). Still, I don't see a whole lot of difference in lifespan. As I mentioned to Rudi, the toner does not seem to react with completely fixed silver compounds. Therefore, if fixing is complete, there won't be much that actually reacts with the toner.

I tone prints in 36-print batches. I use two liters of replenished toner. I have to add 20-25ml of toner concentrate every third or fourth toning session...

As for the ammonium thiosulfate in the toner. I'm sure there isn't much left in my toner except what gets carried over from the second fix and it still tones just fine. Plus, it doesn't have the annoying ammonia smell any longer.

I'm really confident my workflow is sound; I test regularly for both residual silver and hypo and have absolutely no positive results.

Best,

Doremus

M Carter said:

Caught a typo here - "Anything other than a very faint cream color is indicative of inadequate washing" - should be inadequate fixing, as you're testing for residual silver, not residual thiosulphate!

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Thanks for catching that! Too bad I can't go back and edit my post now.

M Carter said:

I just put a drop of straight selenium toner on my prints, after the initial rinse and before going to HCA. After all, there's thiosulphate in the selenium toner, and I don't want to go through the wash process and find I didn't fix enough. Is there a reason to wait til washing is complete to test for silver?

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I'm not sure here. I just re-read Kodak's instructions for both ST-1 and using KRST as a test for residual silver and there is no explicit mention of washing first. But, there isn't for the HT-2 test either, which tests washing... Kodak does say for the residual silver tests, however: "NOTE: The test fails where a very large amount of hypo is present, as in stabilized prints," which would indicate that the hypo (fixer) should be removed by washing before the test is done. However, since I transfer prints directly from fixer to selenium toner with no ill effects, it may be possible to do the test on an unwashed, but rinsed print. Still, I wouldn't trust the test till I had compared it with tests, both positive and negative, on washed prints.

M Carter said:

Also, surprised nobody's mentioned warm water for washing prints. Since diffusion is a chemical process, heat speeds it up. If your paper can handle a warm wash, it will definitely speed your wash and save some time/water (at least in my testing). I can get fiber paper clean (tested with Formulary's RHT) in about 20 minutes. FWIW, here's my process:

2-bath fixing (nobody's mentioned when to decide that bath 2 becomes bath one - for me it's when the strip in fresh fixer test hits 45 seconds or so.

Click to expand...

I'm interrupting here to say, "I did so!" I use throughput as a guide, based on testing the workflow first. For me, that's 35-40 8x10s through a liter of fix 1 before it is discarded. Others can simply use the manufacturer's throughput capacity as a guide for when to change out bath 1. While a clip test is good for film, we should remember that a film fixer can safely have 8-10g/l of dissolved silver in it. Bath one of the print fix shouldn't exceed about 2g/l. I don't think the clip test is sensitive enough to be reliable at this level, nor would the increase in fixing time from that in fresh fix be 2x, as it is for film. If you've tested and found a reliable time-increase factor for a clip test for bath one at that level of dissolved silver, then all is well (and I'd love to have your data if you would be so kind as to share).

And, yes, a warmer wash can indeed speed things up quite a bit. I've seen data on this that suggest that at a too-low temperature, ion exchange slows to the point where washing is practically not happening at all (for those that wash their prints in cold water!). I like ~22°C for my wash.

M Carter said:

I generally test at the start of a session, and maybe halfway through if I'm doing a lot of prints, or there's a lot of high-key fixing going on). A solid initial rinse, print in a tray, at least one change of water, then all prints in a holding bath.

HCA (about a half film vial of Sodium Sulfite to a liter of water). I put about 200ML of very hot water in the graduate to get the powder dissolving, and then top it off from a jug of 1.5% salt water (1/4 cup of canning salt to 1 gallon). 2 minutes of HCA and then into the wash. Often I add a splash of the salt water to the initial wash stage, too (recall reading in one of Rudman's books that "almost anything" speeds the ion exchange, I guess I'm just making my own sea water? may be a waste of time, but it's fairly meaningless time and money to have salt water on hand). A running trickle-wash, pretty warm water, prints separated either in a large tray with bits of PVC pipe on end to keep them apart, or cascading trays - I even have a cascading tray set for 20x24 prints in the bathtub, with a hose running from the shower head - yeah, I need a print washer). After 15 minutes, slowly adjust the water to cold (to harden the paper's emulsion for final handling). Start testing borders after 20 minutes with RHT. Nice clean prints.

When I coat papers with liquid emulsion (for bromoil), it's all cold water though - I don't use a hardener and that stuff is delicate... I swear if you look at it too hard it'll scratch.

Click to expand...

Using salt in addition to the sulfite is likely superfluous. Test show that sodium sulfite, plus a bit of metabisulfite to adust pH, is the most efficient at promoting ion exchange. Plus, the salt in the wash water is just adding more sodium ions to the initial part of the wash, likely slowing things down a bit. Your wash-aid treatment should be adequate to get the paper laden with the right ions (I note, however, that Kodak only recommends 3 minutes in their HCA while Ilford likes 10 minutes in their Wash Aid - I go for the longer time). After the wash-aid step, the prints need fresh water. BTW, HCA is Hypo Clearing Agent and a Kodak product. Homemade wash aid is a different thing

Best,

Doremus

koraks said:

I have the impression that this indeed does happen. I had a large bottle of used selenium toner which went red-brown over the course of a few weeks, suggesting that the selenium went out of solution. Either as a result of a redox reaction not involving any silver, or as a result of combination with silver in solution causing silver selenide to precipitate out. This rendered the toner completely ineffective and I had to dispose of it.

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Koraks,

It's interesting that I've never had anything similar happen to my selenium toner, especially since I reuse and replenish it indefinitely and transfer prints directly from the fix to the toning bath. As mentioned above, I do get a black precipitate, which I filter out, but activity is not significantly reduced and is easily restored by the addition of a small amount of toner concentrate when toning times get too long. I wish I know more about the chemistry going on here.

Best,

Doremus

Doremus, yes, that's also what surprises me. I haven't been able to nail the exact cause down yet. Maybe it's the fixer, maybe it's a specific kind of fixer, maybe it's traces of other compounds sticking to prints (eg when doing selenium after sepia)...
It all goes quite OK with the reuse up to a certain point and then it breaks.

Doremus Scudder said:

As for the ammonium thiosulfate in the toner. I'm sure there isn't much left in my toner except what gets carried over from the second fix and it still tones just fine. Plus, it doesn't have the annoying ammonia smell any longer.

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AFAIK selenium toner is a mix of some selenium salt and lots and lots of Ammonium Thiosulfate. Ammonium Thiosulfate has a pH of about 8 and will therefore smell like Ammonia. Over time it will lose some Ammonia and the pH will drop to a point where it does no longer smell. Absence of Ammonia smell is therefore no proof for absence of ammonium ion.

You can trivially test, whether your selenium toner contains Ammonium Thiosulfate: take a very small sample and add Sodium Hydroxide: if it smells like Ammonia, then there was ammonium ion in solution. Then add a strong acid. If Sulfur precipitates, then you likely had thiosulfate ion in solution.