The Electrolytic Etching of Copper Engravings in Sodium Chloride Solutions.

Investigations were conducted on the electrolytic etching of copper engravings in sodium chloride solutions. Voltage, current, composition of electrolyte, agitation, temperature and position of the plate were studied in relation to the rate of etching, amount of side etching and smoothness of the etched surface. Increasing the voltage, current density, and agitation decreases the amount of side etching and increases the rate of etching. Temperature and plate position are relatively unimportant. In general, the best practical conditions are 10 to 15 volts with vigorous agitation using a saturated solution of sodium chloride.