| 摘要 |
539,724. Etching. KODAK, Ltd. (Eastman Kodak Co.). June 17, 1940, No. 10469. [Class 100 (ii)] A solution for etching zinc contains a copper salt, e.g. the sulphate, and acid sodium sulphate preferably in the form of nitre cake. A small quantity of a substance, e.g. ox-gall, or. " Darvan No. 1 " may be added to prevent adhesion of gas bubbles to the metal surface.
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