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Hypo Clear

Marco B

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OK, so, when your developer is bad, you don't get any blacks... If the stopbad is dead, it turns blue (if it has an indicator like mine), if the fixer is about to go, you can test it using test strips measuring silver content or testing using a piece of undeveloped film...

But how do you know when to ditch HCA???

Or is it one-shot (and what does that mean than?)

When do you ditch your HCA?

As you understand, I only recently bought my first package of HCA, as it won't hurt in processing my fibre based prints, and maybe help the washing and removal of hypo (although I actually don't have a residual hypo test at hand, it has always been based on my feelings, ditching and refreshing water about 7 times in the course of about 1.5 hours as a washing regime).

For those using HCA and using a non-flow washing regime like mine: how often do you refresh water using HCA?
 
The only true test for HCA is to confirm suitably low levels of residual fixer in your print at the end of washing, using HT-2 solution (or probably other mechanisms).

The easiest and cheapest HCA, with best peace of mind, is to buy a tub of sodium sulphite and mix a 20g spoonful into a litre of water each time you have prints to wash. Pour it down the sink at the end of the session.

From the fixer, my prints go into the first water bath to rinse the worst of the fixer off, then into a holding tray until I've built up a few. Then HCA for ten minutes with frequent agitation. Then 5 water baths for at least 10 minutes each, with intermittant agitation. I check finished prints regularly with HT-2 and always get the very pale colour that matches the "archival" spot on the comparison chart.

Ian
 
Stan160 said:
The only true test for HCA is to confirm suitably low levels of residual fixer in your print at the end of washing, using HT-2 solution (or probably other mechanisms). Ian
Click to expand...

HT-2 seems to be discontinued, BH mentions a replacement with Photographers Formulary product:

http://www.bhphotovideo.com/c/produ...rs_Formulary_03_0150_Residual_Hypo_Test_.html

Stan160 said:
The easiest and cheapest HCA, with best peace of mind, is to buy a tub of sodium sulphite and mix a 20g spoonful into a litre of water each time you have prints to wash. Pour it down the sink at the end of the session.
Click to expand...

Is there also something that can be said of the capacity of KODAK HCA working solution (Not stock)? E.g. X sheets of X size paper per liter?


Although I haven't used HCA before, the method you describe for rinsing the prints, is about the same as I do, just with two water baths extra. I haven't seen any signes of pour fixing or remaining fixer causing troubles in my prints, so I guess it isn't to bad, but I think I will try and get that BH listed product to test it once.

Marco
 
Speaking of one-shot & fiber, I wonder if I'm wasting HCA. I currently make an HCA bath for my fiber prints to cut my wash time after fixer, and then put the prints into a new HCA bath to cut wash time after selenium toning. But is the new bath unnecessary? Can I use the original HCA bath the second time?
 

Of course you can use your HCA-bath twice. My capacity estimate is twelve 8x10 sheets per liter. I also stick to the following guidelines:

1. Briefly (5min) wash the print after fixing and prior to HCA to protect the HCA from unnecessary contamination.
2. Never mix HCA used for film and HCA used for paper, because the paper does not like what you are washing out of the film.
 
But I would not use it a third time! And rinse very well before using the fix the first time.

Vaughn
 
Stan160 said:
HT-2 seems to be discontinued, ... I guess the formula is likely to be available somewhere, but I haven't looked.
Click to expand...

HT2 formula

150ml Water
25ml of 28% Acetic Acid solution
1,5g Silver Nitrate
water to make 200ml
 
If you look at the contents of Selenium Toner it is mostly Fixer.

So, a good rinse after the Toning Bath will help extend the life of the Hypo Clear

Marco, I asked the same question here on APUG about 12 months ago and got a similar answer - Hypo Clear activity seems to be a leap of faith

Martin
 
naugastyle said:
Thanks, guys. When you say twelve 8x10s Ralph, you mean twelve prints each washed twice (before and after selenium) in the same bath of HCA, right? I'm mainly printing 5x7s.
Click to expand...

No, I meant a total of twelve prints. Treating a print twice counts as two. But, I am bit conservative when it comes to chemical usage. I rate archival processing above economics. I save my money elsewhere.
 
Thanks all, I will get some residual hypo test and do a test, as I have never really been able to asses it. These specialized products are hard or impossible to find nowadays in normal photo shops.
 
Although I applaud Ralph for being so conservative, I really see no reason to not trust the capacity figures Kodak gives for it's product. If they say 80 8x10 prints per gallon (which translates to 20 per quart or approx. 21 per liter) then that is a figure you can likely trust, with a generous "fudge factor" built in by the engineers at Kodak who developed and tested the product.

As far as contamination goes... HCA works by swelling the emulsion to allow easier and faster washing after the HCA treatment, it does little if any washing of the print itself. While transferring prints directly from the fixer (or selenium toner) to the HCA does carry over residual fixer (toner), Kodak specifically gives different capacity numbers for the two practices. Notice that the 80 8x10s per gallon number is the capacity without a rinse before the HCA. With a rinse, the capacity rises to 200 8x10s per gallon. Again, the Kodak scientists have tested and found the right numbers so that the HCA remains uncontaminated enough to do its job even when prints are transferred directly from the fix. Sure, complex thiosulfates would build up more quickly in the HCA without a rinse, hence the lower capacity.

If you want to be really conservative, cut Kodak's capacity numbers by 10% or so, increase the time in the HCA bath a bit, and wash longer than recommended (I do all three, recognizing that it is overkill to a certain extent). Also note that Kodak does not recommend saving the working-strength HCA solution for later use.

In short, follow the directions and you will be well off

As mentioned, you can mix your own HCA (I do) by simply using one Tablespoon of sodium sulfite plus a pinch of sodium metabisulfite per liter, which I use the same way I would Kodak HCA.

Hope this helps,

Doremus Scudder
www.DoremusScudder.com
 
Thanks for such a detailed response, Doremus. I wasn't thinking just of lowered capacity but also wondering if residual fixer from the 1st soak would cause stains when re-using the bath after toning, which is why I was also going overboard by mixing a second bath. Nice to know that wasn't necessary and I can conserve a bit.
 
Two HT Twos

Marco B said:
Thanks all, I will get some residual hypo test and do a test,
as I have never really been able to asses it. These specialized
products are hard or impossible to find nowadays in normal
photo shops.
Click to expand...

Ilford's 'HT-2': a 1% silver nitrate solution. Kodak's adds acetic
acid. I've tested both. Either is light sensitive, Kodak's less so.
Either one, evaluation must take place immediately
following lights on.

Test drops are to be applied under safe light. Tissue up
excess. Very few minutes are available for evaluation
after lights on.

As the test is done drop by drop, little is used.
I suggest purchase of a small amount of silver
nitrate. White vinegar if you must. Dan
 
I is wise (or necessarily) to treat a FB print in a hypo clearing bath, like 2% Sodium Sulphite, AFTER toning in Selenium?
I use that Hypo clearing BEVORE toning in Selenium.

Thanks,

Philippe
 
  • Deleted member 2924
  • Deleted
dancqu said:
Ilford's 'HT-2': a 1% silver nitrate solution. Kodak's adds acetic
acid. I've tested both. Either is light sensitive, Kodak's less so...
Click to expand...

Dan

It is my understanding that HT2 is Kodak's formula. Ilford has nothing to do with it.
 
There may be a 200 8x10 per gal capacity, but that does not mean it can be stored for months in a partially used state until 200 prints are made. I believe the is either a 30 or 60 day shelf life for the stock. Mixed it is way less.

If you want to be cheap, make up a quart and toss it at the end of the day. One time I errored in ordering and got two 50 gal boxes instead of two five gal from Calumet. I spoon out what I need for a session and I am still working off those two boxes a decade later. Plain Sodium sulphite works also. BTW, 50 gal box is not significantly more money than a 5 gal bag.

Cutting back on what makes a print last is simply not the place to try to save money.
 
The keeping properties (of unused) stock Kodak Hypo Clear solution in a closed container is 3 months. Working solution keeps for 24 hours in a tray. Processing capacity is (80) 8x10 prints without pre-rinse 200 with pre-rinse per gal. I would toss HCA mixed to working strength after 24 hours.
 
Richard Jepsen said:
The keeping properties (of unused) stock Kodak Hypo Clear solution in a closed container is 3 months. Working solution keeps for 24 hours in a tray.
Click to expand...

From all the reactions so far about the keeping properties of HCA, am I right to assume sodium sulphite oxidizes, and that that is the reason for the decay, as with a developer?
 
Kodak's Alone?

RalphLambrecht said:
Dan

It is my understanding that HT2 is Kodak's formula.
Ilford has nothing to do with it.
Click to expand...

That's the reason for the single quotes; ' '. I believe
Kodak did publish that formula but doubt the method
was theirs alone. Maybe back in the 1880s ... Dan
 
Ion Exchange

Doremus Scudder said:
HCA works by swelling the emulsion to allow easier and
faster washing after the HCA treatment, it does little if
any washing of the print itself.
www.DoremusScudder.com
Click to expand...

Although I've not seen it spelled out I believe the
mechanism at work is ion exchange. There is some
swelling of the emulsion. HCAs are, I believe neutral
to a little alkaline.

A preponderance of sulfite ions displaces the attached
silver thiosulfate and thiosulfate ions. NaCO3 also works
well as a HCA and is decidedly alkaline. Dan
 
dancqu said:
That's the reason for the single quotes; ' '. I believe
Kodak did publish that formula but doubt the method
was theirs alone. Maybe back in the 1880s ... Dan
Click to expand...

I don't think we can say that we doubt Kodak did it alone, and therefore, there is an Ilford version of HT-2, which is missing the acetic acid?

HT-2 is a Kodak formula, and I've never seen another HT-2 formula published without the acetic acid.
 

We had a long discussion (there was a url link here which no longer exists) some time ago.
 
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