Ok I feel like a complete dolt... I have subjects coming in tomorrow to have portraits done using my Sabbatair/Solarization technique. I am mixing the chemicals right now... as follows metol 144grams sodium sulphite 440grams sodium carbonite 420 grams sodium bromide 56 grams hot water to make 12 litres....... HORRORS ON HORRORS ... I only have 200 g of sodium carbonate. Ok so its a form of baking soda... somewhat... is there a product at our local food store that I could use ... ie baking soda 200 grams or am I screwed. If I cannot replace the missing 200grams what dire effect could I have by being short of this component. I really am in a spot as our Chemical Dealer is closed, I AM A MORON FOR NOT CHECKING MY CHEMS. any help.