Hypo clearing question

For HCA, I use Steve Anchell's formula, without the sodium bisulfite: 200 grams sodium sulfite in 1 litre of water. This is diluted 1:9 for a working solution, so 1 litre of stock makes 10 litres of HCA. He says that 1 liter can be used for fifty 8x10 prints. Does he mean a liter of working solution or a liter of stock? If he means working solution, then 1 litre of stock will clear 500 prints, which seems a lot. On the other hand, if he means stock, the 1 liter of working solution will clear only five 8x10 prints, which doesn't seem like a lot.

I never mix up stock solution because it doesn't keep very well. I add 20 grams of sodium sulfite to 1 liter of water for a printing session, but maybe I should be making more. Or less. Which?

Doc W said:

For HCA, I use Steve Anchell's formula, without the sodium bisulfite: 200 grams sodium sulfite in 1 litre of water. This is diluted 1:9 for a working solution, so 1 litre of stock makes 10 litres of HCA. He says that 1 liter can be used for fifty 8x10 prints. Does he mean a liter of working solution or a liter of stock? If he means working solution, then 1 litre of stock will clear 500 prints, which seems a lot. On the other hand, if he means stock, the 1 liter of working solution will clear only five 8x10 prints, which doesn't seem like a lot.

I never mix up stock solution because it doesn't keep very well. I add 20 grams of sodium sulfite to 1 liter of water for a printing session, but maybe I should be making more. Or less. Which?

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Here's Kodak's recommendation for HCA, working strength:
12–15 8x10s per liter without pre-rinse
35–50 8x10s per liter with pre-rinse

So, I suspect Anchell is talking about the number of 8x10s per liter of working solution, with a pre-rinse.

It's good you don't mix up the stock; even with the bisulfite added, the solution will oxidize. The working solution without bisulfite (as you mix it) should last for a session, but don't keep it and re-use it. I use 1 Tbsp. of sodium sulfite and a generous pinch of bisulfite per liter, one-shot. It's been working well for years.

Doremus

The Kodak 500gm pack is similarly ambiguous

It says 200 8x10 per gallon and the pack makes up a gallon of stock.

But it caveats this is if an intermediate 1 minute rinse in water is used.

You need to wash the print 10 mins (sw) or 20 (dw) in running 18-21c

My Kodak Pub J-1, Black-and-White Processing Using Kodak Chemicals of 11/85 (page 41) says capacity for a liter of HCA in tray or tank (presumably working strength) is 50 8x10 prints with pre-rinse or 35-50 8x10 negatives with pre-rinse.

mfagan said:

My Kodak Pub J-1, Black-and-White Processing Using Kodak Chemicals of 11/85 (page 41) says capacity for a liter of HCA in tray or tank (presumably working strength) is 50 8x10 prints with pre-rinse or 35-50 8x10 negatives with pre-rinse.

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Here's the correct info (I quoted the tech pub for films above - the capacities are, thankfully, similar).

This is from "CHEMICALS FOR KODAK PROFESSIONAL BLACK-AND-WHITE PAPERS"
A link to the document follows

HCA capacity, 8x10 prints per liter of working solution (the original gives gallon capacities too; I've edited them out)

21 without pre-rinse,
50 with pre-rinse

http://www.kodak.com/global/en/professional/support/techPubs/e103cp/e103cp.pdf

It is interesting to note that Ilford's recommendations for it's Washaid vary somewhat, even though the product is similar to HCA. The informatin below is from the Ilford pdf on Chemical Sudries available here: http://www.ilfordphoto.com/webfiles/2011427101531770.pdf

ILFORD WASHAID Dilution 1+4
Temperature range 18–24ºC (64–75ºF)
Time for FB paper: 20ºC (68ºF) 10 minutes (significantly longer that Kodak)
Time for film 20ºC (68ºF) 2–3 minutes
Capacity– films/litre 2m2 (11 ft2) 40 135/36 films
Capacity – 40 20.3x25.4 cm FB papers/litre (8x10 inch)

The processing sequence is given in the following table

--------------------------- FB paper ---------- film

First wash, fresh running water 5 ------------- 1
ILFORD WASHAID 1+4 .......... 10 ----------2–3
Final wash, fresh running water 20 ----------- 5

Best,

Doremus

As an aside, the bisulfite simply balances the ph helping to reduce curl in some films. I remember I use the bisulfite with roll films as they are curly enough! But with larger sheet film and paper I give them straight sulfite baths.

One thing to note that sulfite oxidizes quickly to sulfate which is photographically inactive. Your working tray is good for about 4 hours then you are just wasting your time. Mix a fresh batch and keep your working solution away from air.

Robert Hall said:

One thing to note that sulfite oxidizes quickly to sulfate which is photographically inactive. Your working tray is good for about 4 hours then you are just wasting your time. Mix a fresh batch and keep your working solution away from air.

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Actually sodium sulfate will work as a wash aid just not as effectively as sodium sulfite. There are other salts that can be used such as sodium carbonate which Agfa recommended for prints. Sodium chloride will also work but again not as effectively.

Gerald C Koch said:

Actually sodium sulfate will work as a wash aid just not as effectively as sodium sulfite. There are other salts that can be used such as sodium carbonate which Agfa recommended for prints. Sodium chloride will also work but again not as effectively.

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Thank you for the correction, Gerald.

Interesting...I've been mixing 100mL of stock HCA for use with film with sodium bisulfite as set out in Anchell's Cookbook. How long does the stock solution keep before going bad?

Thomas

Robert Hall said:

As an aside, the bisulfite simply balances the ph helping to reduce curl in some films.........

Click to expand...

I have read that the small addition of bisulfite, in lowering the pH, brings the swollen gelatin to some sort of optimal state for the diffusion of thiosulfate complexes (for fibre paper).