Selenium toner + HCA - order matter?

Hi there,

I think that I may well have answered my own question but I would like some input from fellow toners!

Using MGWT and Ilford selenium toner I have got used to the time & colour shift at my chosen dilution - I have recently introduced Kodak HCA into my print workflow. I used the HCA before toning and the results were not as expected - litle colour shift and extended times. Thinking that the toner might be exhausted I tried sone scrap test prints from the same printing session, these had barely had a wash just a rinse in a water bath but they toned exactly as expected, so toner ok.

The only difference is the use of HCA after an initial wash & before toning. Why the difference in results?
From my results I will use HCA after toning not before but what is the reason?

Apologies if this is a really daft question.
Sim2.
:munch:

You can actually selenium tone right after the fixing stage, and some photographers do. I give my prints a brief wash though first, as I see no reason to get fixer into the selenium toner if not necessary. So a brief wash for 5-10 minutes in running water after the fixer then selenium tone, then brief wash again, then HCA then final wash. You're all set!

I fix,, wash then HCA, wash then tone.

Not sure why you saw a color shift. You can use HCA before as well but you don't have to. I've never seen a color shift when using HCA before selenium toning.

Maybe the Hypo fills and blocks the pores? That was my best shot at chemistry LOL!

Yep, I normally give an initial rinse before toning then a final wash and am happy with the results, it is my introduction of the HCA before toning that has thrown my regime off kilter - obviously this is the wrong order but why? What is the HCA doing to the prints to affect the toning stage so much. I did not think that residual fixer was needed for selenium toning but seems it is.

*Edit* There was no colour shift when or after being in HCA, prints were as before. There was less than expected colour shift when selenium toning after the HCA than when toning without any HCA.

I use the method outlined in Minor White's book on The Zone System. I give my prints a second fix, no hardener, and then go directly into selenium toner that has been diluted with a working solution of hypo clearing agent (HCA). I've used Kodak HCA, Perma Wash, and Sprint Fixer Remover successfully as well. Then a water rinse, then another bath of HCA, no toner, and then the final wash.

Here I am on my toning soapbox again....

Anyway, there are a couple of issues here to discuss. First, I can see no advantage whatsoever to having an wash-aid (HCA) bath before toning. A wash aid's purpose is to help the prints wash faster, not tone better (in fact, as the OP observes, it can possibly affect toning). Since selenium toner solutions have fixer in them, along with other chemicals, the benefit of using HCA is likely negated somewhat by toning afterwards. Use the HCA just before the wash, as it was intended.

Also there is the question of mixing HCA with the toner. This practice was advocated by Adams, White and others, but has no practical benefit either. And, if you are judging the life expectancy of your toner solution by the life expectancy of the HCA mixed into it, you are likely tossing a lot of still active toner, which is wasteful and environmentally unsound (even municipal sewer systems don't deal well with heavy metals and they just end up in the sludge, making it toxic to a degree).

It may be that the wash-aid before or during toning does not affect its performance, but given the environmental concerns, I think best practice would be to use the toner to exhaustion before discarding (or replenish it) and use a separate wash-aid step. In the "old" days, people were simply not as environmentally aware.

FWIW, my work flow is to double fix, and transfer the print fro the neutral-pH second fixing bath directly into the toner, after about a 30-second drain. This does carry a bit of fixer into the toner, which may reduce it's capacity marginally. I've never experienced any problems doing this (nor did Adams or White) except when the prints were not adequately fixed, in which case staining results (actually a good check on whether the prints are adequately fixed). After toning the prints receive a 10-minute bath in a wash-aid (I mix my own) and then go to the wash. My toning solutions get replenished when the toning times get too long by adding a bit of stock solution. The solution is stored and filtered before using it again. I have a couple of gallons of toner (strong and weak), which have been going like this for way more than 5 years. No problems and all the prints pass residual silver and hypo tests with flying colors and I never have to discard toner.

Best,

Doremus

Double fix, place in holding tray, tone at end of session, and then wash.

Or alternatively, single fix, holding tray, double fix and tone at end of session, then wash.

I use the latter, no issues unless fixer is on last leg (which won't help you either way, washing first, hca or not).

the question of mixing HCA with the toner. This practice was advocated by Adams, White and others, but has no practical benefit either.

Click to expand...

I agree with this poster and his fix/toning procedure with one exception. Rinse prints between the second fix and toning step for NLT 5 min. Follow Ilfords procedures.

Using either an acid stop/acidic fix will slow toning and results in black particles in selenium. TF-4 or another alkaline fix expands the print gelatin and mitigates silver particles building up in the toner. Possible print stains are avoided; the prime reason Adams used a wash aid with toner. This is now an out of date practice.

The only difference is the use of HCA after an initial wash & before toning. Why the difference in results?
From my results I will use HCA after toning not before but what is the reason?

Click to expand...

The post fix wash aid step will allow a shorter, safer wash to eliminate trace hypo which is part of the selenium formula.

The acid in acidic fixer is what makes selenium toner deteriorate. If you use alkaline fixer the print can go straight into the Kodak Rapid selenium toner, which as has been pointed out contains a lot of thiosulphate.

If one were to use a near-neutral fixer, like Kodak C-41 (pH around 6.5), does anyone know if that is acidic enough to precipitate KRST?

Whne Agfa Universal Fixer was available (pH around 7.5) I found that I could put a print directly into KRST after the second fixing bath. I haven't experimented with (expensive) KRST now that the only near neutral fixer I can get here is Kodak Flexicolor or the corresponding Fujifilm one.

I use TF4 and simply ignore all that HCA and double-tray fix headache. Prints are placed in a try of
plain water until the end of the work session when they are toned.

I'm not a photochemist, nor do I play one on TV, but I do know from the MSDS that KRST concentrate contains about 40-45% ammonium thiosulfate aka Rapid Fixer. Whether or not you do HCA before the toner, my view is that it should always be done after the toner to get rid of that thiosufate. The toner does work differently when the print comes straight out of the final fixing bath into it (and IMO works better as in more flexibility) but as someone alluded to earlier, a black precipitate forms in the toner sooner than would happen if the print was washed beforehand. I always assumed the precipitate was silver selenide but I don't know for sure. I always thought the precipitation occurred once the toner solution reached a low enough pH from the act of putting unwashed prints directly into the toner from the fix. Again I assume the toner pH changes depending on the foretreatment of the print.

I would suspect using HCA or another alkali during or before toning changes the toning solution pH (like I assume the added fixer might) and produces a different result.

Based on these assumptions I either do one of these procedures depending on the effect I'm after:

1) Tone the print directly out of the final fixer bath, then HCA and a final wash. This seems to give me better split-tone effects with certain papers at the expense of toner life.
2) After the final fixing bath, I rinse the prints briefly, HCA for 3-5 minutes, then they are fully washed for 30minutes. They are then toned and given a second HCA treatment and another 30 minute wash to remove the thiosulfate present in the toner formula. This takes longer and uses more water, but reduces possible staining or irregular toning and improves the shelf life of the toner. However, I usually prefer the first procedure.

Hey ho, here we go - been back in the darkroom again and reprinted the negs again using MGWT.

As normal prints were put into a holding water bath after fixing till the end of the printing session and then rinsed for about 5 mins in fresh water. Then popped into the selenium toner and hey presto - colour change at the rate/intensity that I would have expected. Then into HCA before final wash for 20 mins. Nice results and better than the first set!

Normally give a longer pre-tone wash and have to dry before toning another day, followed by another long wash, so less washing this way. I did have in my mind that excess fixer carry-over into the selenium would accelerate the forming of solid precipitate particles (which is perhaps where I got the idea of using HCA pre-selenium) and give patchy/inconsistent toning results.

Having a bit of a read around, patchy results are more likely due to insufficient fixing rather than insufficient pre-toning washing. Anyhoo, better finished results now and lessons learned - HCA after selinium toning!

Cheers for the inputs.
Sim2.

Also I've always been under the assumption that adding or carrying over HCA to Se toner will kill it's longevity.

All that really needs to be done is for the print to be fixed completely. This is where double fixing comes in so usefully. And since the print doesn't require a strong wash beforehand more water and time is saved.

Just a funny note: On my Labor Partner Selenium toner bottle it says:Use of furter watering aid is not required (http://www.macodirect.de/rollei-selenia-tonerbrversion-pi-211.html)

So my question is, HCA and final wash after selenium toning is in all above posts said to be important, and all off you is doing it. What has gone wrong in the type writer to the "user manual guy" at Rollei?

DarkMagic said:

Just a funny note: On my Labor Partner Selenium toner bottle it says:Use of furter watering aid is not required (http://www.macodirect.de/rollei-selenia-tonerbrversion-pi-211.html)

So my question is, HCA and final wash after selenium toning is in all above posts said to be important, and all off you is doing it. What has gone wrong in the type writer to the "user manual guy" at Rollei?

Click to expand...

Is there a possibility that it is a different formulation to Kodak Rapid Selenium Toner?

Or, Hypo Clearing agent helps to remove not only straight thiosulphate but also various compounds of thiosulphate and silver. Maybe by the time the print has been toned in selenium it has experienced an extra fix so there are no longer the silver complexes, just thiosulphate which might wash out in water relatively quickly. Just a guess!