Self-Made HypoClear any good?

[RalphLambrecht]

I started to make my own HCA, mixing 20g of sodium sulfite to 1 liter (2%) as a working solution. I noticed that when I poured the solution into the tray that the last 10% or so were not as clear as the rest (the solution is a week old), but it seemed to mix OK.

After fixing, I power-washed for 5 minutes and then used the HCA for 10 minutes, followed by a 30 minute wash. Then, I wiped the prints off (squeegee) and hung them to dry. I noticed later that the wiped-off liquid turned white. Apparently, some of the HCA is still in the print after a 30 minute wash!

Questions:

1. Does the residual HCA harm the print?
2. What is the best way to deal with this?

 

[Ole]

3: A 2% solution of sodium sulfite should be perfectly clear, and not show any sign of sediment.

Since yours did, there's something else in it. My first guess is that it's been mixed with "hard" water, so that you've got calcium sulfite (and sulfate) coming out of solution.

If the wash water is also "hard", you'll have a little calcium absorbed in the emulsion which reacts with the sodium sulfite again, leading to even more white stuff! So it's not the HCA which is still in the prints, it's a trace of calcium sulfite/sulfate.

After washing, give the prints a few minutes in deionised water. Use deionised water for mixing "HCA", or filter the solution before use.

 

[RalphLambrecht]

Ole

Many thanks, that makes a lot of sense, because the prints brown-toned perfectly (sodium sulfite is a toner stop bath). I filtered the solution right after your post, and will use deionized water in the future. Any idea why this never happend with Kodak's or Ilford's WashAid? ... and, do you think it might harm the archival properties of the print?

 

[David Brown]

Ole

Many thanks, that makes a lot of sense. I filtered the solution right after your post, and will use deionized water in the future. Any idea why this never happend with Kodak's or Ilford's WashAid?

I could be wrong, but I have read somewhere that Kodak included in some of their formulas chemicals to deal with the impurities in domestic water. Somebody else will have to confirm this (or refute it).

 

[Ole]

The commercial mixes all contain a sequestering agent (Calgon, EDTA or similar) for precisely this reason.

I wouldn't expect a hint of gypsum to have any serious effects on the longevity, no. After all there's already a layer of barium sulfate in there (baryta)!

 

[Peter De Smidt]

I think Ole is right. I had some serious print staining/cloudy solution problems when I moved my darkroom. It turned out that the water was simply too hard for the sequestering agents to do their job properly. Changing to a better water source eliminated the problems.

 

[Ian Grant]

Both Ilford and Agfa gave details for making your own HCA.

Agfa recommend using Carbonate in their literature for fibre based paper processing, the Ilford bit is in Mason's Photographic Processing Chemistry, (he was head chemist a few years ago) where he recommends using Sodium Sulphite.

The chemicals have no effect on the image at all, they help to make the residual traces of silver complexes formed during fixing more soluble, and so easier to remove.

Most of the research was carried out during WW2 when it was discovered that salt (sea) water used to wash prints on board navy ships accelerated the washing process.

The chemicals used in HCA / wash aids are very soluble in water so wash out extremely quickly.

Ian

I started to make my own HCA,

Questions:

1. Does the residual HCA harm the print?
2. What is the best way to deal with this?

 

[RalphLambrecht]

...
Most of the research was carried out during WW2 when it was discovered that salt (sea) water used to wash prints on board navy ships accelerated the washing process....
Ian

Thanks Ian

This is not the reason for the thread, but the actual research is much older than WW2. The WW2 story is a nice myth; the facts, you stated on the other hand, are true.

 

[dancqu]

Ole

...sodium sulfite is a toner stop bath...

A bit of chemistry trivia. Brown toners are sulfide
toners. Polysulfides are used. Sulfur will dissolve in
sodium sulfide making a Polysulfide. Sulfur dissolves
also in sodium sulfite making Thiosulfate. So, a stop
of sulfite works because it ties up available sulfur.

It MAY be easy to make brown toner. I've some
sulfide solution ready. Wonder if P. Formulary carries
sulfur. Should be interesting and maybe rewarding
to experiment. Dan

 

[RalphLambrecht]

...
Sulfur dissolves also in sodium sulfite making Thiosulfate. So, a stop
of sulfite works because it ties up available sulfur.
...

Dan

Does that mean I'm creating fixer when trying to stop the toning?

 

[dancqu]

Dan, does that mean I'm creating fixer
when trying to stop the toning?

That's my understanding. Not very much though.
Those brown toners are used very dilute. Likely the
sulfur is an easy catch for the sulfite. The sulfur
oxidizes the sulfite to a thio - sulfate. Dan

 

[rjas]

How long can I be saving HCA? I use the powdered kodak HCA packets and just use a tablespoon per liter and have been dumping after every session no matter how many prints I run through because I was told that it oxidized in a matter of hours. Am I wrong in dumping it or can I use it for a couple days? I'm switching to the Ilford Permawash liquid because its all I can get here soon but I still have one last packet of Kodak HCA.

 

[gainer]

You should be able to get sulfur at a druggist, or a farm supply store.

What happened to the theory that HCA is worse than residual hypo? Maybe that was only for the formulae that contained peroxide.

 

[Tom Hoskinson]

You should be able to get sulfur at a druggist, or a farm supply store.

What happened to the theory that HCA is worse than residual hypo? Maybe that was only for the formulae that contained peroxide.

That theory wasn't about HCA (Kodak's Hypo Clearing Agent), Pat - it was about HE-1 (Kodak's Hypo Eliminator - which does contain Hydrogen Peroxide).

 

[Ian Grant]

Back to your original post I'm very surprised that you had any chemicals left in the paper, in 45 years of printing I've never seen what you are describing.

As I said the chemicals used in wash aids / HCA are extremely soluble in water and wash out very easily.

Only two things spring to mind, first the prints aren't being washed properly, maybe they are sticking together, or you have exceptionally hard water. I'm more inclined to go for the latter explanation.

Oh I put a date on the washing in sea-water, perhaps I shouldn't have assumed WW2

Ian

Thanks Ian

This is not the reason for the thread,

 

[dancqu]

How long can I be saving HCA? I was told
that it oxidized in a matter of hours.

It is that uncertainty with the usual sulfite based
HCAs on the market that has me ready to switch to
Agfa's recommended sodium carbonate based HCA.

A study quoted in a post to rec.photo. darkroom
recently told that sodium sulfite was, IIRC the exact
words, "as good as any other". That is, not any better
than some others. I suspect Agfa's recommended
sodium carbonate is as good as sulfite and it
does not oxidize. Agfa's instructions may
still be on the WWW. Dan

 

[RalphLambrecht]

Ian

It turned out to be the hard water. Thanks.

 

[john_s]

It is that uncertainty with the usual sulfite based
HCAs on the market that has me ready to switch to
Agfa's recommended sodium carbonate based HCA.

A study quoted in a post to rec.photo. darkroom
recently told that sodium sulfite was, IIRC the exact
words, "as good as any other". That is, not any better
than some others. I suspect Agfa's recommended
sodium carbonate is as good as sulfite and it
does not oxidize. Agfa's instructions may
still be on the WWW. Dan

However there are many posts on rec.photo.darkroom stating that sulphite is better than carbonate. I agree that carbonate is tempting since it is cheaper and used at a lower concentration and lasts longer in solution. It would be better than nothing.

The Agfa pdfs might not be all findable on the web. I have some of them. FWIW, this text is cut from the most recent pdf on fibre paper:

<start quote>
Soda intermediate bath

A soda bath (1 % sodium carbonate solution) should be included
for fibre-base paper, between fixer and final wash (time: 3
minutes). This ensures that the fixer is washed off the paper
surface faster and more thoroughly.
This not only cuts down the final washing time by about 30 %,
and in particular it increases the prints' durability.
If a hardener-fixer is used, the soda intermediate bath is not
recommended.
<end quote>

In the unlikely event that hardening fixer is used, the carbonate is not recommended because its alkalinity would negate the hardening which is pH dependent. I wonder if the alkalinity would leave the paper emulsion softer which might make it vulnerable to some toning processes.

 

[Wolfgang Moersch]

Ralph

If you prefer a low pH level HCA try this

EDTA4Na 12g or DTPA pentasodium salt (solution) 25ml
Sodium sulfite 200g
Sodium bisulfite 6g
Sodium citrate 4g

to make 1000ml stock solution
dilute 1+9 for working solution

Wolfgang Moersch
www.moersch-photochemie.de

 

[RalphLambrecht]

Ralph

If you prefer a low pH level HCA try this

EDTA4Na 12g or DTPA pentasodium salt (solution) 25ml
Sodium sulfite 200g
Sodium bisulfite 6g
Sodium citrate 4g

to make 1000ml stock solution
dilute 1+9 for working solution

Wolfgang Moersch
www.moersch-photochemie.de

I didn't realize that much sodium sulfite would disolve in water. Couldn't you make this more me? I'm just on the other side of town.

 

[Robert Hall]

I have heard that the working solution is only good for a few hours. If that is the case, how long would the stock solution last?

 

[Wolfgang Moersch]

I didn't realize that much sodium sulfite would disolve in water. Couldn't you make this more me? I'm just on the other side of town.

Ja klar, komm vorbei. Ist alles vorhanden.
Heiss gelöst geht das schon. Man kann aber auch mit einem Liter Wasser starten, das macht den Kohl nicht fett.

 

[RalphLambrecht]

I have heard that the working solution is only good for a few hours. If that is the case, how long would the stock solution last?

Robert

I think your Weston quote has a spelling error. True?

 

[Robert Hall]

Sie haben Rechts, danke mein Herr.

 

[RalphLambrecht]

I guess Edward was right, it's hard work to be perfect (I'm still working on it). This gave me a chance to look at your work. Very impressive!!!