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DIY fixer. This is what you lot really want don’t you. It’s marginally more exciting that the stop bath, promise.
So you’ve gone and listened to a random person online and followed their instructions to make a thick dodgy soup that’s supposed to be a real developer. Good on ya, don’t read any emails from Nigerians. Now you’re left with this weird-smelling boring white Sodium Sulfite powder like a doofus. What better way to use it up than by buying another chemical reagent some Pole tells you to, online.
Nearly every fixer uses hypo, aka sodium thiosulfate. Mix 250g of that for 1l of hypo. That’s it. But the stuff doesn’t like acidic environment – it breaks down into elemental sulphur among other things. Bad for your fixer. And after all the dodgy DIY stop baths there’ll be some acidity to your rinsed film. That’s where Sodium Sulfite comes in, saving the day with its preservative properties, buffering the pH of the fixer making it last months on end.
Sodium Thiosulfate is used in so many applications getting a kilogram (pound?) of the stuff online really shouldn’t be difficult anywhere in the civilised world. It’s sold as a pentahydrate (crystals formed with water molecules) so you’re paying for one part desired chem five parts water. Oy vey. You can get the dehydrated stuff but it usually costs way more. It’s mostly inert, doesn’t like air/moisture and sun (that’s a lie but it’s a good habit to hide any chems you have from the elements, like little pet vampires), you can eat a spoonfull safely and not die the death your stupidity merits.
