Quick question about making D-23.

dcy

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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"?
 
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dcy

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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.
Click to expand...

Thanks!

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

retina_restoration

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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

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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.
Click to expand...

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

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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

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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...
Click to expand...
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

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@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

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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

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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

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

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Saganich

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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

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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

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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

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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

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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.
 
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dcy

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PC-TEA was an interesting example of a formula where it is imperative that one follows the instructions precisely. You have to heat the TEA to pretty high temp to dissolve the ascorbic acid, but that temperature destroys Phenidone. So you need to fully dissolve the ascorbic acid first, let it cool, and only then can you add Phenidone.
 

pentaxuser

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Thanks Donald. Based on the part of your reply that I have put into bold type it would seem that far from ensuring that adding a pinch is the safer thing to do, it make it less safe as only by not adding a pinch of sulfite can you be sure the metol had not oxidised. Adding a pinch of sulfite may disguise the sign that the metol has already oxidised or does it show that it has oxidised to an extent and that extent may or may not indicate the extent to which it is photographically significant and this detrímental to the efficacy of the D23?

However that only serves to introduce uncertainty into whether the D23 will work properly so the only 100% test that the metol has not oxidised at all is to avoid adding the pinch and see if the solution is as clear as possible

If I have interpreted what you have said correctly and I happen to be someone who craves certainty then it sounds better not to add a pinch of sulfite

Any comments confirming my interpretation or explaining why I have interpreted you statement wrongly is appreciated

pentaxuser
 

Milpool

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Adding the “pinch” of sulfite before the metol will not do any harm and poses no risk. It’s just not necessary.

Dissolving the metol in plain water takes little time, during which only a tiny amount of oxidation takes place in the mildly acidic environment. The pinch of sulfite might help lessen or prevent that, but a lack of colouration does not necessarily tell you zero oxidation has taken place anyway since sulfite tends to have a decolourizing effect.

This is essentially a non-issue for D-23 mixing. Either way is fine.
 

Bill Burk

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This is good to know about the pinch, I guess it wouldn't even be a problem if a bit more than a pinch was added. I've noticed that when I mix D-76 from the Kodak package, the thin needles are the last to dissolve, and the last of them will take a long time to dissolve by stirring but they dissolve easily in fresh water poured over them in a filter funnel.

I figured that by the time all the chemicals in the bag are in, the solution is near saturation.
 

Yezishu

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Your experience is valuable, while methods can vary based on the situation. I have an heated magnetic auto-stirrer, so there's no need for high temperatures to speed up dissolution. I simply add everything to TEA and stir at 60-70°C overnight or for a few hours. (Not a suggestion, just a casual chat.)

There are various approaches to achieve the same target if we understand what the goal is, such as using a microwave to heat up TEA to 120°C(manual stirring) or a boiling water bathauto/hot plate to reach 80-90°C(more manual stirring). Each method has its pros and cons. Personally, I prefer avoiding the risk of spilling hot liquid out, though many have the skills to handle it safely and hope to complete the mixing quickly, either way is fine..
 
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Yezishu

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I suspect this is related to the amount of Metol. There is always dissolved oxygen in water, so adding Metol directly will certainly lead to oxidation.
If using some formulas like D-94 or D-97, which contains only 0.5 to 0.6g of Metol per liter of water, even a small amount of oxidation could cause significant differences. While the D-23 formula added 7~10g of Metol, even a 1-gram lost would only result in a 10% variation.
 

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The first pinch of sulfite method dates back to The Amateur Photographers' Handbook, Aaron Sussman, as far back as I know. D-23 was highly regrarded in the Ansel zone system books. Personally I use D-23 because it's cheap and I'm a cheapskate. D-76 is a fine developer also. Frankly I can't tell any difference in results. All that said,commercial D-76 mixes up better and quicker by far. Elon, Metol, or whatever the trade name. Mixed at home as D-23 is a practice in self-abuse trying to get it to mix. Mix up the formula of a pinch of sulfite, all the elon, then the sulfite and come back every 30 minutes for 2 hours or so to give it another stir, and so on. The only difference between metol and sand, is that metol will EVENTUALLY mix, and sand will NEVER mix. There's a reason Kodak marketed D-76 and not D-23 on the consumer market.
 

Raghu Kuvempunagar

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dcy said:
You have to heat the TEA to pretty high temp to dissolve the ascorbic acid, but that temperature destroys Phenidone.
Click to expand...

Doesn't heat degrade Ascorbic Acid as well at a temperature as high as 200 F? According to scientific literature it does and IIRC @albada worked at a much lower temperature for his long lasting Mocon concentrate.
 
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