Photographers' Formulary 50lbs Sodium Thiosulfate (Hypo), Penta (Prismatic Rice)

• In preparation of fixing baths• Ingredient in various reducersNote:Hypo is available in two forms: anhydrous and, more commonly crystalline. Crystalline hypo, when dissolved, lowers the temperature of the water considerably, whereas anhydrous does not. Always begin with water of at least 90deg.F/32deg.C when mixing the crystalline form. Use 64% of the anhydrous salt as a substitute for crystalline hypo.