Bronzing is the operation of covering articles with a wash or coating to give them the appearance of bronze. Two kinds are common, the yellow and the red. The yellow is made of fine copper dust, the red of copper dust with a little pulverized red ochre. The fine green tint which bronze acquires by oxidization, called patina antiqua, is imitated by an application of sal-ammoniac and salt of sorrel dissolved in vinegar. Towards the end of the 19th century bronze was deposited on small statues and other articles with good effect by means of the electrotype process. Research Bronzing