Help in how to make hypo wash aid

[Shmalick]

Hello,



Need help in understand on how to make Hypo Clearing Wash Aid. I have attached a screen shot of recipe and need help to understand what does two red circled water quantities mean.

it says 750ml water to use then at the end stats “ cold water to make 1 liter”. A bit confusing to me. Why two different quantities of water are mentioned. Thanks in advance.

 

[Nitroplait]

same as I wrote on another forum to answer the same question from you:

It just means you have to add water to make up a total of 1000ml.

Mix the first 3 ingredients, it will probably around 850ml give or take. Add water to make 1000ml total and you are done.

 

[xkaes]

That 750ml is really arbitrary. You can start out with 500ml, 600ml, 800ml -- whatever. The important thing is AFTER you have mixed the chemicals in thoroughly, that you ADD water to end up with 1000ml.

The 750ml is just a good place to start -- but I never worry about being exact with the starting water level.

 

[Shmalick]

That 750ml is really arbitrary. You can start out with 500ml, 600ml, 800ml -- whatever. The important thing is AFTER you have mixed the chemicals in thoroughly, that you ADD water to end up with 1000ml.

The 750ml is just a good place to start -- but I never worry about being exact with the starting water level.

Thanks so much

 

[Shmalick]

same as I wrote on another forum to answer the same question from you:

It just means you have to add water to make up a total of 1000ml.

Mix the first 3 ingredients, it will probably around 850ml give or take. Add water to make 1000ml total and you are done.

Thanks. Happy new year.

 

[koraks]

This kind of formula is so non-critical I'd just start with 1 liter, dunk in the sulfite and bisulfite and call it a day.

 

[Shmalick]

same as I wrote on another forum to answer the same question from you:

It just means you have to add water to make up a total of 1000ml.

Mix the first 3 ingredients, it will probably around 850ml give or take. Add water to make 1000ml total and you are done.

This kind of formula is so non-critical I'd just start with 1 liter, dunk in the sulfite and bisulfite and call it a day.

happy new year

 

[Sirius Glass]

Hello,



Need help in understand on how to make Hypo Clearing Wash Aid. I have attached a screen shot of recipe and need help to understand what does two red circled water quantities mean.

it says 750ml water to use then at the end stats “ cold water to make 1 liter”. A bit confusing to me. Why two different quantities of water are mentioned. Thanks in advance.

A number of developers also start with a lesser amount of water to mix with the reagents [liquid or powder] and then once the chemicals are in solution, water is added to the full amount. This accommodates the volume change from adding the reagents and avoids requiring slightly reduce amount of water to start with. This makes getting to the proper strength and volume much easier.

 

[Doremus Scudder]

It's really easy to make a working solution of wash aid, which you can then discard after the session. Stock solutions like the formula in the OP's original post don't last forever (and don't keep the working solution around long at all; it degrades quickly and grows bacterial slime).

My down-and-dirty recipe is: 1 Tablespoon sodium sulfite and a generous pinch of sodium bisulfite per liter. FWIW, I just start with a liter, dump in the chemicals and stir till fully dissolved.

Note that this rather slapdash approach only works for things that don't need a lot of precision. I'd never mix anything critical this way.

Best,

Doremus

 

[Shmalick]

It's really easy to make a working solution of wash aid, which you can then discard after the session. Stock solutions like the formula in the OP's original post don't last forever (and don't keep the working solution around long at all; it degrades quickly and grows bacterial slime).

My down-and-dirty recipe is: 1 Tablespoon sodium sulfite and a generous pinch of sodium bisulfite per liter. FWIW, I just start with a liter, dump in the chemicals and stir till fully dissolved.

Note that this rather slapdash approach only works for things that don't need a lot of precision. I'd never mix anything critical this way.

Best,

Doremus

Thanks

 

[Shmalick]

A number of developers also start with a lesser amount of water to mix with the reagents [liquid or powder] and then once the chemicals are in solution, water is added to the full amount. This accommodates the volume change from adding the reagents and avoids requiring slightly reduce amount of water to start with. This makes getting to the proper strength and volume much easier.

Thanks

 

[Shmalick]

It's really easy to make a working solution of wash aid, which you can then discard after the session. Stock solutions like the formula in the OP's original post don't last forever (and don't keep the working solution around long at all; it degrades quickly and grows bacterial slime).

My down-and-dirty recipe is: 1 Tablespoon sodium sulfite and a generous pinch of sodium bisulfite per liter. FWIW, I just start with a liter, dump in the chemicals and stir till fully dissolved.

Note that this rather slapdash approach only works for things that don't need a lot of precision. I'd never mix anything critical this way.

Best,

Doremus

Thanks

 

[Nicholas Lindan]

FWIW, a formula from Richard Knoppow of the Pure Silver mailing list. Claimed to be (or at least very close to) the formula for Kodak's HCA:

Per liter of stock solution:

5 gm EDTA*
100 gm S. Sulfite
20 gm S. Bisulfite
5 gm S. Citrate

Optional, to taste: Newt eyes, frog toes, bat wool and dog tongue

Dilute 1:4 for use.

Claimed to be buffered to the isoelectric point of gelatin, where the pH is such that gelatine won't hold on to ions.

The quantaties of S. Sulite & Bisulfate in Dormeus' kitchen spoon recipe are close enough to the above that any difference is of no real consequence.

* The EDTA is most likely only needed to keep Calcium salts from falling out of solution.

 

[Randy Stewart]

* The EDTA is most likely only needed to keep Calcium salts from falling out of solution.

What he means here is that tap water may be "hard", i.e., have a lot of calcium compounds dissolved in it. These can precipitate out of solution and attach to your film. However, the EDTA will prevent that for happening. If you do not have a hard water issue, then this may not be needed, or you could mix with distilled or deionized water.