Quick question about making D-23.

dcy · Sunday at 6:31 AM

I think this will be a quick question... I'm watching the step-by-step tutorial from Pictorial Planet for making D-23. The steps are:

1. Add a tiny pinch of sodium sulfite to the water and mix well. This consumers all the oxygen in the water so it won't oxidize the Metol.
2. Add all the Metol.
3. Add the rest of the sodium sulfite.

My question is: Couldn't he just put in all the sodium ~~sulfate~~ sulfite first? [fixed]

1. Add the sodium sulfite.
2. Add the Metol.

Why bother with the "pinch"?

koraks · Sunday at 6:34 AM

dcy said:
sodium sulfate

Sulfite, not sulfate!

dcy said:
Why bother with the "pinch"?

You may find the metol dissolves with more ease before the bulk of the sulfite is added to the water. I think that's the reason.

dcy · Sunday at 6:45 AM

koraks said:
You may find the metol dissolves with more ease before the bulk of the sulfite is added to the water. I think that's the reason.

Thanks!

I was just coming to update my post... I just saw a different video where he says exactly what you just said.

koraks · Sunday at 7:21 AM

Well, always good to get confirmation! Happy mixing!

retina_restoration · Sunday at 9:05 AM

dcy said:
I think this will be a quick question... I'm watching the step-by-step tutorial from Pictorial Planet for making D-23. The steps are:

1. Add a tiny pinch of sodium sulfite to the water and mix well. This consumers all the oxygen in the water so it won't oxidize the Metol.
2. Add all the Metol.
3. Add the rest of the sodium sulfite.

My question is: Couldn't he just put in all the sodium ~~sulfate~~ sulfite first? [fixed]

1. Add the sodium sulfite.
2. Add the Metol.

Why bother with the "pinch"?

Follow the instructions precisely - there’s a reason for it. The pinch of sulfite scavenges oxygen from the water before adding the Metol, which avoids premature oxidation of the Metol (IE: optimizes shelf life). You wouldn’t add all of the sulfite first because that would make it difficult to dissolve the Metol.

pentaxuser · Sunday at 9:23 AM

dcy said:
Thanks!

I was just coming to update my post... I just saw a different video where he says exactly what you just said.

I had thought he had given reasons in the first video but it's been a while since I watched it so maybe not. I have no connection with the person but I have found most of his videos worth watching as I said in a reply to another person

pentaxuser

Donald Qualls · 2025-05-27T08:36:11-0400

This method is the same for all metol-based developers -- add just a little of the sodium sulfite before the metol. I don't know what the trick is for commercially packaged developers like D-76 or Dektol -- I haven't mixed either one from powder (ever, for D-76, and in about 20 years for Dektol) so I've forgotten if they package the developing agents with a little of the sulfite and then the main sulfite load in a separate bag, or all together and somehow get the metol to dissolve anyway...

koraks · 2025-05-27T08:47:41-0400

Donald Qualls said:
if they package the developing agents with a little of the sulfite and then the main sulfite load in a separate bag, or all together and somehow get the metol to dissolve anyway...

It's all together and I think that encapsulation is used to affect the order & rate of dissolution. Maybe @ADOX Fotoimpex could comment on this.

Milpool · 2025-05-27T08:48:58-0400

dcy said:
I think this will be a quick question... I'm watching the step-by-step tutorial from Pictorial Planet for making D-23. The steps are:

1. Add a tiny pinch of sodium sulfite to the water and mix well. This consumers all the oxygen in the water so it won't oxidize the Metol.
2. Add all the Metol.
3. Add the rest of the sodium sulfite.

My question is: Couldn't he just put in all the sodium ~~sulfate~~ sulfite first? [fixed]

1. Add the sodium sulfite.
2. Add the Metol.

Why bother with the "pinch"?

@koraks is correct. If there is any substantial amount of sulfite in solution it will be increasingly difficult to dissolve the metol.

Regarding single packets, at one time Kodak had a series of patents for things like encapsulation, sequestration.

pentaxuser · 2025-05-27T11:13:25-0400

What I find assuring about D23 is that apart from being very easy to make and involving the fewest ingredients possible to arrive at a good developer, is the almost or is that even complete agreement about its make-up and method of make-up

pentaxuser

Milpool · 2025-05-27T11:26:39-0400

pentaxuser said:
What I find assuring about D23 is that apart from being very easy to make and involving the fewest ingredients possible to arrive at a good developer, is the almost or is that even complete agreement about its make-up and method of make-up

pentaxuser

More or less. The pinch of sulfite is not really necessary but doesn't hurt.

The only variation on the make-up is the "teaspoon/tablespoon" measurement method (ie if you don't have a scale), which actually appears in the reputable literature (Haist, etc.). D-23 is simple enough and contains large enough quantities/concentrations of the two ingredients that a reasonable amount of slop can be tolerated.

pentaxuser · 2025-05-27T11:35:14-0400

Milpool said:
More or less. The pinch of sulfite is not really necessary but doesn't hurt.

Most presenters mention the pinch as being important to prevent oxidisation of the metol but your comment relegates the importance to that which Ilford rates the necessity of a pre-wash

So, is there no basis for the "pinch"" If there isn't then the make-up of D23 is even simpler as it then becomes "pour in all the metol then all the sulfite and stir

pentaxuser

Saganich · 2025-05-27T11:36:32-0400

Without the pinch or with a really small pinch the mix will tint towards that brown color that metol has after being on the shelf for a awhile. With a 'good' pinch the D23 stays clear. And yes, all that sodium sulfite will make metol impossible to dissolve. The SS also needs a bit of increased temp (37-40C) to get it all in solution and should be let to cool in room temperature (as opposed to using a refrigerator) else it can precipitate out.

Milpool · 2025-05-27T12:03:43-0400

pentaxuser said:
Most presenters mention the pinch as being important to prevent oxidisation of the metol but your comment relegates the importance to that which Ilford rates the necessity of a pre-wash

So, is there no basis for the "pinch"" If there isn't then the make-up of D23 is even simpler as it then becomes "pour in all the metol then all the sulfite and stir

pentaxuser

Somewhere in time the pinch of sulfite became a thing. It can't hurt, of course. It just isn't necessary.

"Pour in all the metol then all the sulfite and stir" would not be correct. Dissolve the metol fully first, then add the sulfite and dissolve that.

The order is important - all formulas are given (should be given) in the order the ingredients are added, and each ingredient should be completely dissolved before adding the next. That's the best practice you'll find in any reputable book/source.

David Lindquist · 2025-05-27T12:21:11-0400

What my Kodak publication J-1, Processing Chemicals and Formulas for Black-and-White Photography, 1963, says: For one liter of D-23, start with 750 mL water at 50ºC. First dissolve 7.5 grams of Kodak Elon (Metol), then add and dissolve 100 grams of sodium sulfite (desiccated). Add cold water to make one liter. No mention of a pinch of sodium sulfite first.

This is the way I do it (albeit for larger volume) and have not had any problems. I have not done parallel testing to see if the addition of a pinch of sulfite gives a developer with greater activity or longer shelf life.

David

pentaxuser · 2025-05-27T14:25:28-0400

David Lindquist said:
What my Kodak publication J-1, Processing Chemicals and Formulas for Black-and-White Photography, 1963, says: For one liter of D-23, start with 750 mL water at 50ºC. First dissolve 7.5 grams of Kodak Elon (Metol), then add and dissolve 100 grams of sodium sulfite (desiccated). Add cold water to make one liter. No mention of a pinch of sodium sulfite first.

This is the way I do it (albeit for larger volume) and have not had any problems. I have not done parallel testing to see if the addition of a pinch of sulfite gives a developer with greater activity or longer shelf life.

David

Thanks for that I just had a look at another current thread asking about the differences between D76 and D23 and in that thread at least 2 respondents mention the useful oxygen scavenging effect of a pinch of sulfite

It seems to me it either works and is worthwhile all the time or it doesn't work and there are good chemical reasons why not or it works under certain circumstances/conditions which may be present when making D23 and just in case those conditions may exist of which it may be impossible to know for definite it makes sense to use the pinch

So maybe we need to turn our intentions towards what those conditions might be. If we can be sure that they don't exist when you make D23 we can then do exactly as Kodak recommends. It certainly simplifies matters if Kodak instructions can be always be followed, no matter what

pentaxuser

Donald Qualls · 2025-05-27T15:27:21-0400

It's easy to see the metol solution change color if you mix that ingredient without the pinch of sulfite, in any developer formula that uses metol. That color change is (as far as I know) due to oxidation of the metol in solution. Given the short time frame (generally) between mixing the metol to full dissolution, and adding the sulfite and mixing that (generally the second ingredient in metol-based developers), the amount of oxidation is probably not photographically significant, but it bothers some workers. I, for instance, prefer my stock solution to be as clear as possible, to make it easier to tell if there's a problematic change.

Quick question about making D-23.

dcy

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Quick question about making D-23.

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