Sulfite of Soda Sodium sulfite anhydrous Disodium sulfite Sulfurous acid, disodium salt Exsiccated sodium sulfite
Appearance
White Granular Crystals, or powder
Uses
As a preservative of developing agents Constituent of the acid fixing bath Blackener in negative intensification Active energizer in amidol development To clear Polaroid Type 55 black & white negatives
Chemical Formula
Na2SO3
Notes
Sodium sulfite is the most widely used preservative in developers. It also plays an important part in the process itself.