Okay. I am certainly no chemist. Was looking at this website devoted to producing HHO gas (hydrogen gas from water) to supplement petrol in your car. I stumbled across a clip showing a guy mixing up a solution of what he called sodium acetate, which is used to prevent the water in his hydrogen chamber from freezing during winter...he mixed plain old white vinegar and baking soda. I thought I'd mix some up with a sprinkle of tartaric acid ( I read somewhere that tartaric acid helps keep highlights from muddying) and develop a kallitype print (2 tblspns baking soda, 250ml vinegar, half tspn tartaric acid, distilled water to make 1 litre...I'm sure I could have used tap water, oh well). Adding vinegar to the baking soda makes for a fine display of sizzling which subsides in about a minute or so. I mixed in a ventilated area but I really don't think it's that toxic...but better to be safe than sorry. With the addition of tartaric acid there was some more sizzle but not as much. It all mixed to a nice clear solution. The print is blacky browny egg planty. Whites are really nice and clean (cleared in citric acid). I used Rising Stonehenge paper. I think next time I'll try it with double the amount of baking soda and slightly less tartaric acid to see if that affects print colour. So does baking soda and vinegar when mixed together become sodium acetate?