copperas

Logwood dyes lilac, or pink; to turn red hackles brown, boil them in copperas.

Copper dissolved in the vitriolic acid forms crystals of a blot colour, called blue copperas.

Boil the logwood for 30 minutes in a gallon of water, and then add the copperas and lampblack.

The hypo., when thus affected with the copperas, appears also to throw a mist over the picture, which new hypo.

When such is the case, only about 1⁄6 or 1⁄7th of their weight of copperas should be employed.