Sodium thiosulfate is one of the few know substances that will dissolve silver bromide. As such it is universally used in modern photographic procedures.
In this process known as "fixation," the unexposed silver bromide is dissolved in the sodium thiosulfate by combining with it to form soluble complex thiosulfates of silver and sodium.
Hypo Hyposulfite of soda Sodium hyposulfite Sodium subsulfite Sodium thiosulfate, pentahydrate Thiosulfuric acid, disodium salt, pentahydrate
Large white monoclinic, colorless crystals and powder
In preparation of fixing baths
Ingredient in various reducers
2S 2O 3.5H 2O
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 90°F/32°C when mixing the crystalline form. Use 64% of the anhydrous salt as a substitute for crystalline hypo.
Box Dimensions (LxWxH)
4.9 x 3.0 x 3.0"
Photographers' Formulary Sodium Thiosulfate, Anhydrous - 1 Lb. Review
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