Sodium sulfate/bisulfate interchangeable?

Richard Wasserman · Dec 24, 2007

I think I probably know the answer to this, but I thought it's worth a try anyway. I will be mixing TD-201 film developer from The Film Developing Cookbook and the formula calls for 40 grams of Sodium sulfate in the B solution. I do not have Sodium sulfate on hand, but do have Sodium bisulfate, can I use this instead? I'm hoping it's close enough with maybe an adjustment in the quantity? Thanks!

Richard Wasserman

Photo Engineer · Dec 24, 2007

You cannot use them interchangably but you can adjust for one or the other. To do that, you need to know the desired pH value of the solution you are making and then adjust accordingly with either dilute Sulfuric Acid or dilute Sodium Hydroxide.

So, unless you really want to do this and know what you are doing, I don't recommend it.

PE

Richard Wasserman · Dec 24, 2007

PE, thanks, that is pretty much what I was expecting (although hope springs eternal!). Looks like it's time to place another order for chemicals.

Richard

Tom Hoskinson · Dec 24, 2007

Richard, a PM to billtroop should give you an answer the TD-201 B solution pH question and to other questions as well.

gainer · Dec 24, 2007

While you are waiting for the sulfate to arrive, you might try the experiment suggested in Anchell & Troop. Add about 30 grams of sodium chloride (I think the type labelled "Canning salt" and perhaps Morton's non-iodized salt will be pure enough, as it has no iodide) in place of the sodium sulfate.

Photo Engineer · Dec 24, 2007

Sodium Chloride and Sodium SulFITE are mild silver halide solvents and have no relationship to Sodium SulFATE or Sodium BisulFATE which are not silver halide solvents.

So, unless the OP meant Sodium SulFITE and Sodium BisulFITE, the post by Gainer has no relationship to the OP.

PE

gainer · Dec 24, 2007

Photo Engineer said:
Sodium Chloride and Sodium SulFITE are mild silver halide solvents and have no relationship to Sodium SulFATE or Sodium BisulFATE which are not silver halide solvents.

So, unless the OP meant Sodium SulFITE and Sodium BisulFITE, the post by Gainer has no relationship to the OP.

PE

The post by Gainer has a definite relationship to the developer in question. It was not my idea. I simply called attention to the passage in "The Film Developing Cookbook." I quote:
"To increase the fine grain effect of the two-baths below, add about 30 g/l of sodium chloride (common salt, but use a laboratory grade) to either the A or B solution- or both. The result would be something like a two-bath version of Microdol, which would eliminate the need for sodium sulfate in the second bath."

Tom Hoskinson · Dec 24, 2007

Photo Engineer said:
Sodium Chloride and Sodium SulFITE are mild silver halide solvents and have no relationship to Sodium SulFATE or Sodium BisulFATE which are not silver halide solvents.

So, unless the OP meant Sodium SulFITE and Sodium BisulFITE, the post by Gainer has no relationship to the OP.

PE

PE; To quote Anchell and Troop (page 84 of The Film Developing CookBook):

To increase the fine grain effect of the two-baths below (i.e. Stoeckler, Dalzell, Adams, Leitz, TD-200, TD-201), add about 30 g/L of sodium chloride, ( common salt, but use a laboratory grade) to either the A or B solution - or both. The result would be something like a two-bath version of Microdol, which would eliminate the need for sodium sulfate in the second bath...

Photo Engineer · Dec 24, 2007

Tom Hoskinson said:
PE; To quote Anchell and Troop (page 84 of The Film Developing CookBook):

To increase the fine grain effect of the two-baths below (i.e. Stoeckler, Dalzell, Adams, Leitz, TD-200, TD-201), add about 30 g/L of sodium chloride, ( common salt, but use a laboratory grade) to either the A or B solution - or both. The result would be something like a two-bath version of Microdol, which would eliminate the need for sodium sulfate in the second bath...

That would be correct Tom, but you cannot use Sodium Chloride instead of a Sulfate / Bisulfate mixture for pH buffering, but you can use it to assist solvent effects for Sodium Sulfite. So, a solvent developer can contain mixes of the sodium salts of Sulfite/Bisulfite/Chloride in appropriate ratios or alone as in D-76 and Mocrodol.

BUT - you cannot use Either sulfites or halides to replace Bisulfate/Sulfate mixtures which are used for buffering.

Threfore either the original post was referring to a silver halide effect (-ITE) or a pH buffering effect (-ATE). If it was the former, you and Gainer are right and the OP was incorrect, but if the OP was correct, then Gainer was incorrect and your post, while correct, misinterprets the reason for my comment and Gainer's both.

PE

DarkroomExperimente · Dec 24, 2007

OK...does this mean NaCl & Sodium Sulfite together can work as a mild restrainer?

or am I confusing restrainer & solvent?

[ I just ordered some KBr last night...and it's supposed to show up tomorrow...nuthin' says Christmas like darkroom chemicals ]

gainer · Dec 24, 2007

Photo Engineer said:
That would be correct Tom, but you cannot use Sodium Chloride instead of a Sulfate / Bisulfate mixture for pH buffering, but you can use it to assist solvent effects for Sodium Sulfite. So, a solvent developer can contain mixes of the sodium salts of Sulfite/Bisulfite/Chloride in appropriate ratios or alone as in D-76 and Mocrodol.

BUT - you cannot use Either sulfites or halides to replace Bisulfate/Sulfate mixtures which are used for buffering.

Threfore either the original post was referring to a silver halide effect (-ITE) or a pH buffering effect (-ATE). If it was the former, you and Gainer are right and the OP was incorrect, but if the OP was correct, then Gainer was incorrect and your post, while correct, misinterprets the reason for my comment and Gainer's both.

PE

Your problem, not mine. I did not in any way say that salt was equivalent to sulfate. I suggested trying the experiment suggested by Anchell & Troop while waiting for the sulfate to arrive. You are so intent on proving me wrong about anything I say that you are making a fool of yourself. The original post was referring to a particular formula and so was I. If anyone is wrong, it is Anchell & Troop, and their sugested experiment did not claim that chloride and sulfate are the same, but that if the chloride is used, the sulfate ought not be necessary.

dancqu · Dec 24, 2007

disfromage said:
I will be mixing TD-201 film developer from The Film Developing
Cookbook and the formula calls for 40 grams of Sodium sulfate
in the B solution. Richard Wasserman

Just checked with A&T. They suggest using sodium
chloride as substitute for sodium sulFATE; bath
A or/and B for that Microdol effect.
Don't blame me.

BTW, via Google, TD-201 film developer . Interesting
two bath D23 types detailed. Dan

Photo Engineer · Dec 24, 2007

DarkroomExperimente said:
OK...does this mean NaCl & Sodium Sulfite together can work as a mild restrainer?

or am I confusing restrainer & solvent?

[ I just ordered some KBr last night...and it's supposed to show up tomorrow...nuthin' says Christmas like darkroom chemicals ]

You are confusing solvent with restrainer.

A solvent dissolves grain and is used in Microdol and D-76 (Sodium Chloride and Sodium Sulfite respectively).

A restrainer slows down development, lowers fog, lowers contrast and decreases speed. It is usually used to restrain fog.

PE

Photo Engineer · Dec 24, 2007

gainer said:
Your problem, not mine. I did not in any way say that salt was equivalent to sulfate. I suggested trying the experiment suggested by Anchell & Troop while waiting for the sulfate to arrive. You are so intent on proving me wrong about anything I say that you are making a fool of yourself. The original post was referring to a particular formula and so was I. If anyone is wrong, it is Anchell & Troop, and their sugested experiment did not claim that chloride and sulfate are the same, but that if the chloride is used, the sulfate ought not be necessary.

I am intent on clarifying either the OP or the advice given regarding it, or a possible misprint in A&T. See Dan's post.

You cannot and should not use Sodium Chloride to replace Sodium Sulfate or Sodium Bisulfate.

Let us be clear that Sodium Chloride, Sodium Bisulfite and Sodium Sulfite are mild silver halide solvents and are used that way in many film developer formulas.

Let us be clear that mixtures of Sodium Bisulfate and Sodium Sulfate make a buffer solution. One cannot be substituted for the other unless the final pH is known and corrected for by addition of Sulfuric Acid or Sodium Hydroxide.

Whoever suggests otherwise has made a misstatement.

In reference to the OP, your answer was not clear and you appear to have missed (as I did, but as Dan has caught) that there is apparently a misprint in A&T. After all, you did equate Sodium Sulfate with Sodium Chloride in its action in a developer thereby perpetuating, not catching the error.

I postulated an error in the OP, not thinking of there being an error in A&T. It is pretty good in that regard and Bill has an errata section on his web page (or at least he did).

PE

Jordan · Dec 24, 2007

I don't have Anchell and Troop in front of me, but I doubt highly that sulfate and bisulfate form a buffering solution that would even be remotely useful in photography. The pKa for the second ionizable proton in sulfuric acid is 2, which is far too low for any photographic process that I can think of (except dichromate or permanganate bleaching, which is generally not carried out in a buffered solution).

I do remember reading of some other photographic uses of sodium sulfate -- in developers meant for use at high temperatures, IIRC. I don't know what the mechanism of action is.

The issue here seems to be that A&T suggest a couple of different "variants" on the same developer, and some are assuming that these variants are meant to produce the same result or have the same chemical function. From the OP, that isn't clear to me, and so it's probably not useful to speculate further until someone posts the relevant section of A&T here.

Photo Engineer · Dec 24, 2007

Jordan said:
I don't have Anchell and Troop in front of me, but I doubt highly that sulfate and bisulfate form a buffering solution that would even be remotely useful in photography. The pKa for the second ionizable proton in sulfuric acid is 2, which is far too low for any photographic process that I can think of (except dichromate or permanganate bleaching, which is generally not carried out in a buffered solution).

I do remember reading of some other photographic uses of sodium sulfate -- in developers meant for use at high temperatures, IIRC. I don't know what the mechanism of action is.

The issue here seems to be that A&T suggest a couple of different "variants" on the same developer, and some are assuming that these variants are meant to produce the same result or have the same chemical function. From the OP, that isn't clear to me, and so it's probably not useful to speculate further until someone posts the relevant section of A&T here.

Jordan;

You are entirely correct. The buffer point is too low, but given the popularity of the acidic Amidol developers and other variants, I was not willing to argue based on that point alone. That is why I suggested that the OP might be wrong. It seems that A&T may also have an error.

But, there seemed to me to be also some off chance that this was used in a carbonate or borax developer as a swell supressant which is another thing I considered. It is used in tropical developers to prevent excessive swell as you point out.

PE

DarkroomExperimente · Dec 24, 2007

Photo Engineer said:
A restrainer slows down development, lowers fog, lowers contrast and decreases speed. It is usually used to restrain fog.
PE

thanks....

gainer · Dec 24, 2007

First let me state that I am dreadfully sorry that I made that comment about PE's motives. I know that if we were together in the same room, we would not have had some of the interchanges you have seen here. I am old enough to spend a lot of time talking to myself about dumb things I do. "Gainer, you ass, why did you do that?" I used to have interactions with office mates that made witnesses think we were deadly enemies, and then we would take a break, go out to the Coke machine, flip to see who paid, go back into the fray, and eventually solve the problem.

The stated function of the sulfate in the original recipe was in fact to reduce swelling of the emulsion. The chloride is not as effective in that function, but it serves the additional function of silver halide solvent. I would assume that is why A&T suggested that if sodium chloride is added, the sodium sulfate should be left out. The OP simply wanted to know if sulfate and bisulfate were interchangeable, and there was nothing wrong with PE's reply. My comment was in effect, here is a good reason to try the experiment suggested by A&T because ir might take a week or more to get sodium sulfate, but non iodized salt is commonly available at the grocery store, and at least it's food grade, and canning salt IIRC is maybe even better.

Emulsion swelling is a subject of considerable discussion in Mees & James, as I know PE knows quite well, and there is a list of various salts in order of their ability to promote swelling, but no numerical values attached. Sulfate is least likely to promote swelling and chloride is about halfway up the list. There is also the statement that in an alkaline developer, the thing that keeps the alkali from excessively swelling the emulsion is the salt content, meaning salt in the general way, not specifically sodium chloride.

I am not telling PE anything new, as he illustrated in Post #16 above. It seems strange to me that no one has read A&T's rationale for the original formula or that for the suggested revision. It's in Chapter 9 under the subheading D-23 two-bath developers.

Tom Hoskinson · Dec 25, 2007

See this Thread: (there was a url link here which no longer exists)

Also see: Modern Photographic Processing, Grant Haist, Vol. 1, 1978, page 379 tells us:

"According to Van Veelen and Peelaers, Sodium Chloride, added in a high concentration to a developing bath of low activity, dissolves silver bromide or idobromide and solution physical development can occur.

Less salt (i.e. less than 30 grams/liter) is said to give more grain but increase film speed."

Mick Fagan · Dec 25, 2007

Regarding Sodium Sulphate Na2 SO4, I know of two main uses. The main use I have of this chemical photographically, is, as an ingredient in B&W tropical developers.

Its main purpose is to reduce the swelling of the emulsion, which, when that happens to an extreme, the emulsion will lift off and is poured out with the developer, I have had this happen. The result, is very patchy negatives.

I currently have about half of a 10 kg container of this stuff (technical grade).

The formula that I have used quite extensively when I lived in a very hot part of the country and the cold water temperature was approximately 30 C was this:-

Metol 2 gm
Sodium Sulphite Anhyd 50 gm
Hydroquinone 5 gm
Potassium Carbonate 30 gm
Sodium Sulphate 45 gm
Potassium Bromide 1.5 gm
Water to 1 litre.

Development time is about 2 minutes at 30 C or 2 ¼ minutes at 29 C with Plus X film. You cannot use a pre-wet at this temperature and you have to use the developer neat.

That other use I know for this chemical is for medicinal purposes, would you believe?

It is commonly sold under the name of Glaubers Salts! The German chemist Glauber, found that taking this salt mixed in water, had a purging effect and therefore cleared the intestines of unwanted matter.

I can testify that its cathartic effect is relatively quick, not necessarily painless, but, it works.

Mick.

Photo Engineer · Dec 25, 2007

As Patrick says, Sodium Chloride in high enough concentration can reduce swell. In fact, a number of chemicals can do this, but the Sodium Chloride has solvent effects which can overwhelm the swell effect and this is why Sulfates are chosen.

A mixture of Sulfate and Bisulfate in either an acid or basic solution before development, and which contains formalin or succinaldehyde or glutaraldehyde can be a very effective hardener. The basic solution is much more effective.

Prehardener

Water 800 ml
Formalin 37% 10 ml
Na2SO4 50 g
Na2CO3 50 g
pH to 10.0 with NaOH or H2SO4
Water to 1 L

Use for 1 - 3 mins, then wash for 5' before development. This will harden a soft film product for use in solutions up to 100F.

And Patrick, Merry Christmas. I do wish we could meet in person. There is so much we could teach each other.

PE

DarkroomExperimente · Dec 25, 2007

not to mention how much you could teach me - last night I got the book "Caveman Chemistry"

....I haven't even learned to make by fire by rubbing sticks together yet

Photo Engineer · Dec 25, 2007

I make emulsions by rubbing two silver halide molecules together in the presence of gelatin.

Next time you come to the George Eastman House, give me a call or join one of our GEH lunches. There will be up to 6 or more of us there at one time. We talk about Darkroom Experiments!

PE

gainer · Dec 25, 2007

DarkroomExperimente said:
not to mention how much you could teach me - last night I got the book "Caveman Chemistry"

....I haven't even learned to make by fire by rubbing sticks together yet

It's not easy. It's somewhat easier if you use the bow method.

"Caveman Chemistry" is a good book, and fun to read even if you know everything that's in it.

Sodium sulfate/bisulfate interchangeable?

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