Precision hydrometer calibrated for specific densities between 1,000 g/cm3 and 1,100 g/cm3

Silver nitrate baths used in the wet plate process are a 9% silver nitrate solution in distilled water. That means 90g of silver nitrate dissolved in one liter of distilled water. Once we prepare this mix, there is only one way to find out how much silver nitrate there is in the bath: we need to measure the specific density of the solution with a hydrometer.

A 9% silver nitrate bath has a specific density of 1,067g/cm3. If our bath has a lower density we will have to add silver nitrate to the mix