Potassium salts are said to give warmer tones.Originally Posted by don sigl
The MWs are:
So if a recipe calls for potassium carbonate 200g and you have sodium carbonate anhydrous, the eqivalent amount of the latter is:
200 x 106/138.2 = 153g
But the result is likely to be different because the potassium carbonate was probably chosen to make the image warmer.