selenium toning and borax

What about borax prior to selenium toning?

Though I really like the improvement in blacks and tonality from selenium toning, I had not done it much for years, because I've ruined too many prints with stains. Mixing up a bath of plain hypo as a presoak works fine to avoid staining, but it's too expensive and too much trouble.

I recently read that the stains really don't come from small amounts of residual hypo in the paper or emulsion as photographers used to think, they come from residual acid. So I tried a tablespoon of household 20 Mule Team Borax in a gallon of water as a presoak. Beautiful results, no stains.

Did I just luck out? Has anyone tried this? Any reason why it might be a problem?

Some of us use alkaline fixer to avoid the problem of acid causing problems with selenium toning. It looks as though the borax is alkaline enough. For how long did you soak the prints in the borax solution?

That's an interesting observation Andrew. Another interesting fact is that Agfa suggested a 1% sodium carbonate bath for 3' as a hypo clearing agent for FB prints. Sodium carbonate would certainly neutralise any acid left, it's cheap and it's aqueous solutions have excellent shelf life, as opposed to sodium sulfite. I'm not sure about it's effectiveness as a washing aid compared to sulfite though.

An other treatment prior to Selenium, is soaking for 2 min in 2% Sodium sulfite, this is what I do. But, I do fix in a neutral fixer (Fuji’s Unilec 1+4) and give it a short rinse after the fixer, and I use a buffered stop bath (+/-pH 5,5).
It works well and the KRST (1+9) has a long lifespan this way.

Philippe

There is more than one cause of staining:

1) Insufficient fixing leaves some silver salts in the emulsion, selenium toner will 'tone' these salts to a reddish color. The stain is usually blotchy, staining the parts of the print where the fixer didn't get to because of poor agitation, print floating on the surface or prints sticking together.

2) Expired fixer produces an overall stain because there is silver salt left everywhere in the emulsion.

3) Prints taken from heavily used fix straight to the toner can develop a blotchy overall stain because the carried over fixer contains a lot of dissolved silver, which the selenium again gleefully tones.

4) Acid fix can cause staining in heavily used Se toner where prints are transferred from an acid fix with insufficient washing and carryover has used up the pH buffer in the toner. More often, the carryover results in the precipitation of black gunk in the bottle of working toner solution. Kodak, an advocate of acid fixers, used to recommend diluting the toner in HCA. This practice would have increased the buffering capacity of the toner but the resulting mixture would last only as long as it took to oxidize the sulfite in the HCA, usually a matter of hours. The technique was only useful in large commercial operations where the toner would have expired by the time the HCA oxidized and the resulting toner mix would be disposed of. Kodak has removed this recommendation as it doesn't work in amateur darkrooms.

I think the only guarantee of no-stain toning is a 3rd fix in fresh fixer (which is rotated through to the 2nd fix, which becomes the first fix, which is disposed of) followed by a rinse, HCA and a good rinse/wash.

A light alkaline bath before the toner may be extra insurance but the carried over alkali will eventually, again, use up the buffering capacity in the toner. I don't know the effect of extra alkali in Se toner, but it shouldn't be hard to find out - put a teaspoon of borax or carbonate in the toner and see what happens. Sulfite may be a better choice as an alkalizing bath as it would oxidize in the used toner to neutral sulfate.

john_s said:

Some of us use alkaline fixer to avoid the problem of acid causing problems with selenium toning. It looks as though the borax is alkaline enough. For how long did you soak the prints in the borax solution?

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I didn't time it, on the theory that (hopefully) the borax would not do anything but de-acidify the paper and emulsion. Around 10-15 minutes I would guess, while I was doing something else.

Howard Bond showed us his method for holding and selenium toning prints and I have never had a stain. After fixing, you hold the prints in a very weak solution of wash aid (I have held them overnight with no problems) and tone them in a mixture of wash aid and selenium toner, I use a normal dilution of wash aid and 1+9 of toner into this. I save it in a brown glass jug, pour off the clear toner for new use and replenish 25%. Wash normally, seems to work well....Evan Clarke

After my 1st fix bath I place all prints in a water holding tray. At the end of the session I then pass them all through a 2nd fix bath, into a smaller tray of water and then all through Se toner. Never have stains. You don't need to do anything fancy you just need to make sure your prints are completely fixed and not loaded with acid. Also don't use hca for simple clearing, use sodium sulfite powder from PF. 1lb is about 12-14 dollars and you only need around 5g per 1000ml.

second fixer bath

A second fix in plain sodium thiosulfate always works, but I don;t know if it's because it neutralizes any acid or because fixing is often not complete. Since I toss solutions loing before exhaustion, I suspect the former.

Andrew Kleinfeld said:

A second fix in plain sodium thiosulfate always works, but I don;t know if it's because it neutralizes any acid or because fixing is often not complete. Since I toss solutions loing before exhaustion, I suspect the former.

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Actually 1st bath fix usually breaks down exponentially fairly quick. It's not that it's unusable, but it won't get everything. I'd say second bath fixing is a *very good idea* for most people. One can use the 1st fix deep into use and the 2nd bath will always completely clear components the 1st bath wasn't able to. How long do you let your prints drain before transferring trays btw?