sodium acetate as a developer anhydrous or trihydrate?
I want to use sodium acetate as a developer for kallitypes. I live in the uk and the only cheap sodium acetate i can get is the trihydrate stuff. what is the difference between the anhydrous and the trihydrate sodium acetate? and can i use the trihydrate?
Matt, just the molecular mass differs between them; anhydrous = 82g / mole, trihydrate = 136g / mole.
If your formula calls 350g "anhydrous" sodium acetate per liter but you have trihydrate on hands, then:
136g (trihydrate) / 82 g (anhydrous) * 350g (anhydrous equiv.) = use 580g (trihydrate equiv.)
Hope this helps,
Trihydrate is hydrated.
I imagine you would need to use more of it in a recipe that asks for anhydronous as above.
You should be able to heat it up to dehydrate it, though unecessary, you can also make it with bicarb + vinegar (trihydrate).
Silverprint sells sodium acetate in the anhydronous form for about 15 pounds if you really want it.
Thanks for that info guys. I had seen the anhydrous stuff on the silverprint website but compared to the trihydrate on eBay it's very expensive so I shall give it a go with the trihydrate and report back.