When new, ferric chloride is a clear red/brown color. There are a few visual cues that assist in determining the efficiency of a ferric bath. The most reliable source for 48 baume (Be) ferric chloride, commonly used for photogravure, is FUJIFILM Hut Chemicals Specialty Products Group. A hygrometer is used to measure the baume of the ferric chloride. If ordering an already dilute, 42 baume (Be) solution, there is no need to adjust the solution with the addition of water.Ī ferric chloride etching bath is most effective after a bit of etching has taken place.
Ferric chloride is free from harmful gas emissions it will stain but will not burn skinįerric chloride is available from most chemical suppliers in the less saturated 42 baume. Ferric chloride has virtually replaced the use of nitric acid and Dutch mordant as a solution for etching copper. Although etching is commonly considered a process of using acid to bite the metal, ferric chloride is actually a corrosive salt. Ferric chloride has the advantage of greatly improving the safety of etching.