D23 - Sodium Sulfite or Sulfate ??

yossi · Sep 18, 2022

Hello everyone,

I am trying to mix some D23 developer. I am going to use this recipe:

Then I found another YouTuber saying instead of Sodium Sulfite, it should be Sodium Sulfate Andydrous !!
Now I am confused. Which is the correct one?

Could some experts here help me with a definite answer before I mix my first D23 please. TIA

yossi

Zathras · Sep 18, 2022

Hi Yossi,

The correct chemical is Sodium SULFITE, anhydrous.

BradS · Sep 18, 2022

to be clear, Sodium Sulfate and Sodium Sulfite are very different.
Sodium sulfite, whether anhydrous or crystaline is NOT the same as sodium sulfate.

anhydrous just means, 'dry'. If left in air, sodium sulfite will absorb some small about of water from the air and no longer be anhydrous. Whether you use the anhydrous form of Sodium sulfit or not when mixing D23 will make little difference. If you're feeling pedantic, you can adjust the weight to account for the added water...but, again, it doesn't really matter in D23.

but definitely use sulfite NOT sulfate.

yossi · Sep 18, 2022

Zathras said:
Hi Yossi,

The correct chemical is Sodium SULFITE, anhydrous.

Yay! I got the correct one, luckily.

Thanks Zathras & BradS for the confirmation. D23 here I come

albada · Sep 19, 2022

You might be able to buy sodium sulfite in Singapore, and have much lower shipping costs. An internet search shows several companies there that sell it. It would be a pity to pay long-distance shipping for something obtainable locally.
Anyway, enjoy the D23.

yossi · Sep 19, 2022

Wheee!

Supposedly it needs 1-2 days to fully settle before use.

yossi · Sep 19, 2022

albada said:
You might be able to buy sodium sulfite in Singapore, and have much lower shipping costs. An internet search shows several companies there that sell it. It would be a pity to pay long-distance shipping for something obtainable locally.
Anyway, enjoy the D23.

I have tried buying the chemicals locally but no luck (these Co. mostly sell the chemicals in bulk). You are right about the high shipping cost. I paid almost double the cost of the chemicals just to ship them over from the US. No choice.

albada · Sep 19, 2022

yossi said:
I have tried buying the chemicals locally but no luck (these Co. mostly sell the chemicals in bulk). You are right about the high shipping cost. I paid almost double the cost of the chemicals just to ship them over from the US. No choice.

Buying 100 Kg of sulfite in bulk will make you shoot film for the rest of your life. And think of all the shipping cost you saved.

Anyway, I've never heard of needing to season D23 by waiting 1-2 days. I thought it could be used immediately after mixing. In fact, you might consider mixing only the amount you need soon before using it, and then discard it (using it "one shot").

yossi · Sep 19, 2022

albada said:
Buying 100 Kg of sulfite in bulk will make you shoot film for the rest of your life. And think of all the shipping cost you saved.

Anyway, I've never heard of needing to season D23 by waiting 1-2 days. I thought it could be used immediately after mixing. In fact, you might consider mixing only the amount you need soon before using it, and then discard it (using it "one shot").

100kg? Good idea hahaha!
But I won't just use D23 for life. I prefer the Rodinal look atm.

Btw what is the typical shelf life of a newly brewed D23?

juan · Sep 19, 2022

Do you have home brewing or small brewers there? You may be able to buy small quantities of sodium sulfite there.

yossi · Sep 19, 2022

juan said:
Do you have home brewing or small brewers there? You may be able to buy small quantities of sodium sulfite there.

Good idea. Thanks. I have already purchased 2Lb of Sodium Sulfite from B&H. It should last me for quite a while. I will see if I like the result or not first before sourcing for more Metol and Sodium Sulfite.

Donald Qualls · Sep 19, 2022

Another potential source of sodium sulfite is from swimming pool and hot tub/spa suppliers. It's one of two chemicals used to reduce chlorine levels in the water. The other is sodium thiosulfate, which is plain hypo fixer. It's easy to tell them apart when you open the container; the sulfite will look like granulated sugar, while the thiosulfate is long, slippery crystals shaped more or less like a grain of rice (but often larger). Unfortunately, it can be hard to distinguish between them from the package labeling -- in the US, asking for the MSDS should tell the tale, or UN compliant shipping documents would anywhere.

pentaxuser · Sep 19, 2022

yossi said:
But I won't just use D23 for life. I prefer the Rodinal look atm.

Btw what is the typical shelf life of a newly brewed D23?

Well I can't think of 2 developers whose look are more different so if it is the grainy Rodinal look you like then D23 may not be for you but you won't know until you see prints of both a Rodinal negative and D23 negative, preferably of the same scene in very similar light conditions

In a PET bottle I think John Finch says at least 6 months. By the way if you haven't seen his video about making it and its properties it is worth a look

youtube.com/watch?v=H1vWa6fF4FA

pentaxuser

Donald Qualls · Sep 19, 2022

Also, if you can source borax (getting more difficult in some locations, like EU) or sodium metaborate, IMO it's worth replenishing D-23.

grain elevator · Sep 19, 2022

Just for completeness, it's also a food preservative so might be found wherever producers of preserves, sauces etc. shop. Just need to make sure not to confuse it with metabisulfite, which has similar uses in food preservation and brewing, but a very different pH.

juan said:
Do you have home brewing or small brewers there? You may be able to buy small quantities of sodium sulfite there.

pentaxuser · Sep 19, 2022

I think it was Ian Grant who posted in a thread many years ago that sodium sulfite was used in swimming pools so, yossi, are there suppliers of this to swimming pools in Singapore? If you can find such a supplier might he not be peruades to give you a small amount such as a few kilogrammes?

pentaxuser

ags2mikon · Sep 19, 2022

The first time I got sodium sulfite It was brought to me by a friend of my dad who worked at a boiler site in the petro industry. It was in a bag like cement and about 75 pounds. He said they used it by the truck load. They use it as an oxygen scavenger to stop corrosion. As Mr Qualls said pool supply outfits will also be your friends. Also replenishing D-23 is a good idea. I am doing a test on D-23 1:1 replenishment using the replenisher diluted 1:1. About 5 months and 20 rolls. So far so good.

john_s · Sep 19, 2022

Donald, the appearance of chemicals can vary from country to country (crystal size, fineness of powder etc), so not a reliable way to identify.
Also some pool chemicals are below even technical/photographic grade. I bought some years ago (can't remember the compound offhand, but it was something common which is normally soluble) to clarify water in a rural swimming pool that had come from a creek and the label said something like "may contain up to 23% insoluble impurities." Obviously an extreme example.

john_s · Sep 19, 2022

A few years ago, there was a fashion to add sodium sulphite to Rodinal to tame the grain. It converted Rodinal into an ordinary developer. I could never see the point of it myself.

Nicholas Lindan · Sep 19, 2022

Sodium Sulfate Na2SO4 is what happens to Sodium Sulfite Na2SO3 when it absorbs an oxygen.

S. Sulfite acts as a preservative, absorbing oxygen that would otherwise degrade the developing agents, as an alkalizing agent, taking an O from H2O and leaving behind an OH radical, and as a silver solvent reducing grain size.

S. Sulfate is pretty much inert and doesn't do much of anything. It is added to tropical developers to keep the emulsion from swelling, so it has a place in D-23 if you plan on developing at 85F (which my darkroom sometimes gets to in the summer).

S. Sulfite absorbing oxygen from the air is what makes HCA go bad after a few hours in a tray.

I have to confess that I am practicing chemistry without a license (unless a year of freshman chemistry counts). Take everything with a pinch of sulfite (hey, it's an anti-oxidant, it has to be good for you...).

john_s · Sep 19, 2022

Nicholas Lindan said:
......

I have to confess that I am practicing chemistry without a license (unless a year of freshman chemistry counts). Take everything with a pinch of sulfite (hey, it's an anti-oxidant, it has to be good for you...).

This is a bit off topic:

A few years ago it was reported in our main serious newspaper that a medical researcher said that aerobic exercise should be avoided because all that oxygen depletes the body's anti-oxidants, and if you really had to exercise like that, the best thing you could do immediately afterwards was to take a decent dose of anti-oxidant like red wine. Seriously. Needless to say I took his advice.

yossi · Sep 19, 2022

ROTF

yossi · Sep 19, 2022

pentaxuser said:
Well I can't think of 2 developers whose look are more different so if it is the grainy Rodinal look you like then D23 may not be for you but you won't know until you see prints of both a Rodinal negative and D23 negative, preferably of the same scene in very similar light conditions

In a PET bottle I think John Finch says at least 6 months. By the way if you haven't seen his video about making it and its properties it is worth a look

youtube.com/watch?v=H1vWa6fF4FA

pentaxuser

Hi p,

Just watched John Finch’s excellent video. 6 months is more than enough for me. Great!

yossi · Sep 20, 2022

pentaxuser said:
I think it was Ian Grant who posted in a thread many years ago that sodium sulfite was used in swimming pools so, yossi, are there suppliers of this to swimming pools in Singapore? If you can find such a supplier might he not be peruades to give you a small amount such as a few kilogrammes?

pentaxuser

Hello pentaxuser,

I searched for swimming pool chemicals suppliers and found that one company is selling 97% pure Sodium Sulfite in tons (US$400/ton)! Customer could buy samples at $50/kg (min. order 1kg) though. However, this sample price is much higher than what B&H is charging, so no good. In the end, I found the cheapest option is to buy it from small photography supply stores in China via AliExpress, about $10/kg.

(Next is to source for cheaper Metol...Photography is a rich men's hobby Haiz)

Donald Qualls · Sep 20, 2022

john_s said:
the appearance of chemicals can vary from country to country (crystal size, fineness of powder etc), so not a reliable way to identify.

Yes and no.

If you're getting sodium thiosulfate that isn't the long, slippery monoclinic crystals, it's probably not pure enough for either swimming pools or photographic use. Likewise, sodium sulfite sold as a chlorine reducer, if not white and in small granules, probably isn't a good source.

D23 - Sodium Sulfite or Sulfate ??

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