Acetic Acid as stop bath

Hi all,

 

I'm starting the Dark art of Photography.

 

Yesterday, i went to local store to buy the developing chemicals and

other stuff required..

 

He gave me a D-76 as developer, Acetic acid as stop bath and hypo (In

a dry state, crystal form). I'm little confused ..

 

Acitic acid and hypo are locally made and have no details. Should I

make a stock sollution of all the three and use it..? How much to use.

for say 3 roll tank..

 

The three roll tank is of 1 Liter capacity..

 

Aravind

The dilution details for D76 are on the tin/packet. Mix that up acording to the instructions and store in an air-tight bottle. In what form is the acetic acid? Is it glacial (i.e. concentrated) or is it 80% ? This needs to be diltued to give a 2 percent solution. As for the hypo, is it just pure sodium thiosulphate or a brand-name fixer? If plain hypo then use 240 gm per litre of solution (i.e dissolve 240 gm in 750ml warm water and then top up to 1 litre. But note that it doesn't keep well. As a general note, keep all chemicals in air-tight bottles and label them clearly.

 

A 3-reel (35mm) Paterson tank takes 900 ml of liquid.

Thanks Chris,

 

I understand about the developer part, D76.

 

The container of the acetic acid has no technical details. There is only one lable, which states it is for the photographic use only. (Ch3C00h).

 

I can make a stock sollution of Acetic acid and I should make the hypo sollution when required?

 

Should i keep all these in Light safe containers as well?

 

Aravind

None of these chemicals are light sensitive. It is just some tradition that chemicals are kept in brown bottles.

 

As Chris says, you have to find out the concentration of the acetic acid. The standard stop bath is 48 ml of 28% acetic acid per liter of water, or equivalent. Be careful not to splash the acetic acid into your eyes, etc.

Hello Mr. Briggs:

Tradition or not, brown bottles in and of themselves are not light inhibitors. That being said, unless you are dealing with silver nitrate, light restricting bottles are not a requirement for photogaphic chemicals.

Photographic acetic acid is most commonly sold in two strengths: glacial and 28%. There's no simple, safe way to tell which it is, but if it doesn't give a strength, it's likely glacial; you'll need to dilute 3 parts acid into 8 parts (by volume) of water (add the acid to the water, never the other way) to make 28%, which is a sort of stock solution, and then dilute that at 48 ml to the liter of working solution to make standard stop bath at 1.4% strength.

 

There are other strengths sold, though; Kodak Indicator Stop Bath uses one part concentrate to 63 parts water to make working solution, which makes it at least 2/3 the strength of glacial (it may *be* glacial, if Kodak specifies a 2% instead of 1.4% working solution). Best thing is to ask the store where you bought the acid what dilution to use to make stop bath working solution. In the absence of an indicator (a yellow/orange color that will change to purple when the stop bath is exhausted), you may wish to use the stop bath "one-shot" -- discard it after each roll of film or printing session. You can also use plain white distilled vinegar, diluted 1 part vinegar to 3 parts water; depending on the local economy, this may even be cheaper than buying photographic acetic acid (here, it's cheaper to buy stop bath concentrate than vinegar, but that may not be the case everywhere).

 

For your hypo, the simplest use is to dissolve the hypo just before use. I'm used to liquid rapid fixer, but it looks like straight hypo like that should be mixed at 25% strength; that is, 250 g in a liter of working solution. This strength should be capable of fixing about a dozen rolls of 120 or 35 mm/36 exposure film per liter; you'll need to keep track of your use and discard the fixer when it's had that much film fixed in it. Alternately, you can mix fixer at 1/5 this strength, just what you need immediately, and use it once, then discard. Either way, you can test for correct fixing time by dropping a film leader into a graduate of fixer and timing how long it takes for the leader to completely clear, then fix for twice this long. However, if you use T-grain type films (Kodak T-Max, Ilford Delta, Fomapan Creative 200, or Fuji Acros 100), you should use two fixer baths at the one-shot strength, each for twice the clearing time, and discard both after using; these film types are difficult to fix in plain hypo and will exhaust the hypo much more quickly than conventional films.

Thanks Donald,

 

Really apprecieate it..

 

Aravind

I seldom ever use a stop bath other than water and I will do the stop bath twice to lessen the contaminates to my fixer. Years ago I used 1:25 white vinegar to water solution for stop. I have negs now several years that is holding its own without noticable change. Besides any neg of any importance are scanned and recorded on CDs. Oh by the way I process in a JOBO.