(Polysulphide) post-toning hardening bath

henpe · Aug 1, 2020

Many instructions on polysulphide toning recommend to treat the prints in a post-toning hardening bath. My question is, where to get such a hardener these days?

I know Tetenal market a hardener, but the instructions says "Hardens the emulsion of films and papers. For use in either the stop bath or fixer." Does anyone know if the Tetenal product is intended only as an additive (as indicated), or can it also be safely used as a "stand alone" hardening bath (mixed with just water)?

(I know i can mix my own Kodak F-5a hardener, but it is difficult for me to get the raw chemicals...)

Grateful for advice!

/Henrik

MattKing · Aug 1, 2020

I buy concentrated Kodak Rapid Fixer in the one quart containers. It comes with a small (3.5 oz) bottle of concentrated hardener which you don't have to add to the fixer, and I don't. For use, mix it one part concentrate to 13 parts water. I've never been able to find any capacity information.

koraks · Aug 2, 2020

You may be able to find food grade potassium alum quite easily. There are formulas around for making a hardener using that and probably some sulfite and a pH buffer. I never really looked into it (mostly because I just ignore the post-sulfide hardener advice; never noticed any problems), but I'm sure it's doable with pretty generic chemicals that are easy to get.

pentaxuser · Aug 2, 2020

henpe said:
Many instructions on polysulphide toning recommend to treat the prints in a post-toning hardening bath.

/Henrik

Can you say what the source or sources of this advice is/are i.e. in which articles/books does this advice appear and do the sources of this advice explain why hardener is needed?

Thanks

pentaxuser

MattKing · Aug 2, 2020

The instructions for the toners include this advice.
I use a post hardening bath after bleach and redevelop sepia toning and after brown toning.
It is clear to me that the toned image is more fragile after toning, so I use hardener before the final wash.

Arthurwg · Aug 2, 2020

I've been using Kodak Poly Toner for years. I'm actually down to my last bottle, primarily because a little goes a long way. But I have not needed a hardener as far as I can tell. Tim Rudman in "The Photographer's Toning Book" recommends using a hardener with polysulphide toners and gives the following formula for Hardener F-5a Stock Solution: Water at 125 F, 600ml. Sodium Sulphite anhydr 75g. Acetic acid 28%, 235ml.. Boric acid crystals, 375g. Potassium alum (dodecahydrated). 75g. Water at 68F 1000ml.

henpe · Aug 3, 2020

Thank you all for your valuable input.

With your input, and with some more reading-up by myself, I have now found that:

In "The film developing cookbook" (by B. Troop and S. Anchell), the authors suggest that an acid post hardener containing potassium alum should be fine for post hardening (ie after washing). Further, they recommend Kodak F-5 or F-6 hardening bath.
As described above (and elsewhere), Kodak F-5a hardener stock solution contain approx 12 % potassium alum and 10 % acetic acid (by weight).
The MSDS for Tetenal Hardener indicate that the product contain acetic acid in the range 10 - 25% and potassium alum by 10-25%.

Comparing the Tetenal Hardener MSDS with the recipe for F-5a I conclude that the ready-made product from Tetenal should be good for use as a post-toning hardening bath. I hope my conclusion is correct.

Regards
Henrik

koraks · Aug 3, 2020

I think it'll work just fine! Go ahead and give it a try.

Christiaan Phleger · Aug 3, 2020

I did a lot of toning back in the day and from my experience the hardening wasn't a requirement. Even in Hawaii with 25-28C wash water as long as I did not leave the prints washing too long and they did not rub in the wash I could skip the hardening step. The emulsions can be quite delicate with S toning.

(Polysulphide) post-toning hardening bath

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