Reusing Stop and HCA solutions

agenkin · Mar 16, 2007

Greetings:

I am starting out with B&W film processing. For developing film, I'm using, among other chemicals, Ilfostop stop bath, and Kodak HCA. I'm a bit confused whether I can safely keep and reuse the working solutions for the stop and HCA.

The Ilfostop's material sheet suggests that a working solution can be kept for 7 "working days" (got this info from here). What does "working day" mean, really? If I keep it longer (say, a month), will the indicator in it show if it "went bad" (whatever that could mean)?

In Kodak's HCA's package (as far as I remember, can't find the data online) said that the stock solution can be kept for 3 months, but the working solution - for a much shorter time, I don't remember.

For how long is it practically safe to store working solutions of ILFOSTOP and Kodak HCA?

While I'm at it, another question: when I drain out the HCA after usage, it sometimes has a slight pink colour (it has no colour to start with). Is this normal?

Thanks!

Ryuji · Mar 16, 2007

If you are an attentive user, and if the stop bath is of the "indicator" type that changes its color from yellow to violet when it exhausts, you can use it as many times as you want until it changes color, or until when you notice mold or something grows in it.

HCA should be kept in full, tightly closed bottles. If you keep it in ideal condition, you can reuse the solution several times. The thing is that HCA is air-sensitive. There is no good way to tell whether working strength solution is still good or not.

If you use HCA on films, it's normal that you see some color in the used solution. The color is due to dyes that got washed off the film. They usually settle as dark stuff at the bottom of the storage bottle. They break up to very fine particles that easily go through coffee filter. If it bothers you, just decant it and throw a bit away. Don't bother with filters. After all, HCA is much easier on the water treatment plant when you dump, compared to developers or fixers. When in doubt, replace HCA. There's no easy test for whether HCA is still good or not.

Akki14 · Mar 16, 2007

I've had a bottle of working solution stop bath going for about 3-4 months at least at the moment. It's the kind with an indicator and if there's a few drops of print developer in the tray after I empty everything out, i put it in the few drops of stop bath in the stop bath tray just to see if it does still change colour. It does but it always seems like you nearly need an equal amount of developer to make the stop bath change.

eddym · Mar 16, 2007

I reuse indicator stop bath until it is just beginning to change color; it's a subtle shift, so don't wait until it's completely purple.
I discard the working solution of HCA (I use Zone VI) with each use. It's cheap.

Konical · Mar 16, 2007

Good Morning, Arcady,

The comments above are correct. I routinely cover my stop bath tray with thin plastic (the stuff from the dry cleaning shop) floating on the liquid surface; the working solution keeps for many weeks without changing color. For HCA, better to dump it early rather than trying to save a few pennies. Permawash instructions indicate that a working solution in an open tray becomes ineffective in about six hours. For film, you can re-use the HCA, but, to me, the cost saving is too little to justify the bother of having another bottle to store.

Konical

fschifano · Mar 16, 2007

Kodak's HCA, or any other company's wash aid, is not much more than a sodium sulfite solution.; and sodium sulfite is a very good oxygen scavenger. That's one of the properties that makes it so valuable as a preservative for developers and lots of other photo chemistry and also why HCA loses its potency after a very short time. It is also very good at getting the magenta stain off Kodak's TMax films, but that's another story.

I think the most economical way to go about this is to buy some dry sodium sulfite powder, mix up the chemistry as needed, then toss it after use. It is completely unnecessary for resin coated papers. These can wash out completely in as little as four minutes in a good print washing arrangement. The same goes for film, though you might want to consider a longer wash time, or use the Ilford washing method. There is a formula for a washing aid at the digitaltruth web site here: http://www.digitaltruth.com/techdata/washaid.php

Lee Shively · Mar 16, 2007

As others have stated, you can reuse the stop bath numerous times until exhausted. The indicator type will change colors to let you know when that happens. As a precaution, I generally dump mine pretty often. If I have a printing session that has had a number of prints go through the solutions, I don't even check the stop, I just pour it out. It's cheap and easy to mix, so why not? Stop bath stock solution will last for years. I've never had any go bad no matter how long it has been setting on the shelf.

As for the wash aid, you can tell when it's exhausted--sort of. The stock solution will lose its slimey feel when it's dead. It lasts a long time in stock solution, however. I mix my own wash aid from sodium sufite and sodium metabisulfite. It's cheap to use so I don't attempt to save the working solution. I use it with film as well as papers and dump it after each session.

dancqu · Mar 16, 2007

agenkin said:
Greetings: I am starting out with B&W film processing.
For developing film, I'm using, among other chemicals,
Ilfostop stop bath, and Kodak HCA.
I'm a bit confused whether I can safely keep and
reuse the working solutions ...

You can safely do without those two solutions. It is
common knowledge and practice to do without both
when processing FILM. Water rinse twixt developer
and fixer. After fix I suggest a quick rinse then the
Ilford sequence. The last, already mentioned.

Use of a jug of room temperature water will make for
a more thorough cleaning in the same amount of time
and with the same amount of water. I use distilled
because of Hard tap water. Dan

agenkin · Mar 16, 2007

What's the Ilford sequence? Is it the 5, 10, and 20 inversions rinse method that's in their booklet?

Thanks!

dancqu · Mar 17, 2007

agenkin said:
What's the Ilford sequence? Is it the 5, 10,
and 20 inversions rinse method ... ? Thanks!

That's it. I do a relaxed version. After a very dilute one-shot fix
the sequence is started. I do allow for the number of inversions
and the three wash waters. The amount of time for each wash
varies as I'm sure some time left still allows for a cleaner wash.
That still time is well spent rinsing tanks etc.

If you use a one-shot developer along with a one-shot
fix, water rinse and water only wash you'll have no
used chemistry aging away. Dan

Richard Jepsen · Mar 17, 2007

I would add caution that a HCA treatment is necessary for prints to be considered archival in a short wash using one fix tray. Another issue is the number of prints you can run though a one tray fix. Ten 8x10s per L is recommended after HCA treatment. The alternative is to wash longer. After a HCA treatment David Vestal recommended 60m wash with overnight soak. But, he used fix with some hardener due to ground water issues.

The recommendation to mix your own from dry chemicals is sound.

dslater · Mar 18, 2007

I have to wonder why would you want to reuse stop bath? the stuff is dirt cheap. Kodak indicator stop from B&H is $5.69 for enough to make 8 gallons of working solution.

Reusing Stop and HCA solutions

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