fixer mixing ratio question

[atlcruiser]

This might be stupid but.....


following Michael A Smiths fixer recipe for azo paper.....

Using sodium thiosulfate crystals he says 32 oz by volume to one gallon of water. Is this as simple as 2 lbs of sodium dissolved into one gallon of water?

I was never good at chemistry

thanks
david

[Vlad Soare]

I don't know about volume, but two pounds of crystallized thiosulfate per gallon is right (or 1.3 pounds per gallon if it's anhydrous).