Salt Print Chemistry: Concentrations and Safety
This page covers the key chemicals in salt printing, how to mix them correctly, and how to handle and dispose of them safely.
Silver Nitrate Preparation and Storage
Always use distilled water — tap water contaminates the solution.
Silver Nitrate Preparation and Storage
Weigh 12g of silver nitrate crystals and dissolve in 88ml of distilled water in a glass bottle. Swirl until fully dissolved. Store in a brown or amber glass bottle away from light — silver nitrate is photosensitive and degrades when exposed. Label clearly with contents and concentration. A 12% solution keeps for several months if stored properly.
Sodium Thiosulfate Fixer
Mix 100g per liter of water — it needs no temperature precision.
Sodium Thiosulfate Fixer
Dissolve 100g of sodium thiosulfate crystals (photographer's hypo) in 1 liter of room-temperature water. Stir until fully dissolved. This produces a working fixer. Fix salt prints for 2 to 3 minutes with gentle agitation. A fixer bath turns visibly yellow when exhausted from silver uptake — discard and mix fresh.
Silver Nitrate Disposal Spent silver nitrate must not be poured down household drains. Collect in a labeled container. Neutralize by adding sodium chloride (salt) to precipitate silver chloride out of solution — filter and dry the silver chloride precipitate for metal recovery. Check your local regulations for photochemical waste disposal.