Hipo clearing agent formula

[Jorge Prat]

Hi. Can somebody tell me the formula of Hipo Clearing Agent? I can't buy it in m y country, so I need to make the formula by my self with a local lab or somethin g.

Thanks in advance

Jorge

[pat krentz]

Kodak HE-1: water 500 cc Hydrogen Peroxide (3%) 125 cc Ammonia (3% solution) 100 cc add water to make 1 Liter

Wash the prints for 30 minutes at 20 C, the soak in solution for 6:00, then wash for 10:00 and dry.(Photo Lab Index 1947)Pat

[Eugene]

Jorge, Pat gave you the formula for Hypo Eliminator Solution. Do not use it! Hypo clearing agent is sodium sulfite. If possible, obtain a copy of The Darkroom Cookbook, by Stephen G. Anchell.

[Ed Buffaloe]

See the Formulas page at Unblinking Eye (http://unblinkingeye.com).

[Doremus Scudder]

Jorge, just so you don't have to go searching around for your formula or spend extra time weighing out chemicals, a hypo clearing solution can be made by using one Tablespoon sodium sulfite per liter. Capacities will be similar to Kodak's recommendations: Papers; 200 8X10's per gallon. films; 160 4X5's per liter with a water rinse before treatment, papers; 80 8X10's per gallon, films; 50 4X5's per liter without the water rinse. Note: Do not use Hypo-Clear with Pyro developers!

Sodium sulfite is a common chemical available from photo stores, but more cheaply from chemical suppliers. Regards, ;^D)

[Andrey Vorobyov]

Eugene Doremus is right. The recipe told by Pat Krentz is a so-called "hypo eliminator" and should be used for papers only (even thought there are an information that it may cause some the color shift).

The sulphite-based Hypo-Clear can be used both with papers and with films (although film can be efficiently washed without any special means).

[Andrey Vorobyov]

sorry, should be read: "Eugene AND Doremus are right"

[pat krentz]

I must have mis-understood what you wanted, sorry, Pat

[Richard Knoppow]

Kodak Hypo Clearing Agent is proprietary but this is probably the formula. In any case it will work.

Stock Solution Sodium Sulfite, dessicated 100.0 grams Sodium Bisulfite 15.0 grams Sodium Citrate 1.0 gram EDTA Tetra-Sodium Salt 1.0 gram

Dilute 1 part stock solution to 4 parts water for use. Treat film for 2 to 3 minutes and wash for 5 minutes. Treat single weight prints for 2 to 3 minutes and wash for 10 minutes. Treat double weight prints 3 minutes and wash for 20 minutes. The Sodium Citrate and EDTA are to prevent a deposit of Calcium Sulfite on the film in very hard water areas. The wash aid will work without them if the water is not too hard. Sulfite alone will work. Kodak buffers the solution to about neutral for two reasons. First, it minimizes emulsion swelling. That minimises the diffusion path length and increases washing rate a little. The second reason is that it is a pH at which the hardening action of alum hardeners is still effective but at which the mordanting effect the hardener has on thiosulfate is no longer effective.

[peter schrager]

Richard's formula is fine..is that for 1 liter of stock??..permanent wash is getting too pricey!!

[LabRat]

Peter,

The dilution is listed for 1:4... The simple homebrew clone is (for DWFB); sodium sulfite 40 gm/liter, 2-3 min in solution (after 10 min wash), and then as full of a wash as you have time to give (like an hour, with plenty of water changes)...

Using HCA only helps cut the wash time a little with DWFB, so there's nothing like a full wash... HCA can sometimes leave a slight haze over low key prints and soften/swell the emulsion while wet, so consider that...

And the use of a ammonium thiosulfate fixer over using a sodium thiosulfate (hypo) fixer will wash out faster...

And a stronger fixer (like film strength) with a shorter fixing time allows less penetration into the paper base, so it is easier to wash out the thiosulfate complexes that get "caught" in the base paper fibers...

Steve K

[Jim Noel]

Richard's formula is fine..is that for 1 liter of stock??..permanent wash is getting too pricey!!

That formula is also more pricey than necessary. Sodium sulfite is the important ingredient. All the others are basically just add ons.I have used nothing but Sodium sulfite for more than 50 years with no problems.

[Doremus Scudder]

My down-and-dirty recipe is one Tablespoon of sodium sulfite plus a generous pinch of sodium metabisulfite per liter to make a working solution. The problem with making stock solutions is that they don't last very long. Better to just have the dry ingredients around and mix up what you need when you need it. Although the sulfite will work well alone, adding a bit of metabisulfite brings the pH of the solution closer to the emulsion's iso-electric point which facilitates washing.

You don't need the EDTA (sequestering agent) unless you have hard or mineral-laden tap water. If so, especially if you have iron in your water, then add EDTA or sodium hexametaphosphate (Calgon). This latter can be used at concentrations up to 1g / liter of working solution. Add it after the sodium sulfite is completely dissolved to avoid scum. Richard's recipe is very good and is essentially the same as Kodak's HypoClear.

Best,

Doremus