Although the demand in this country for whites ground in water without size for fresco or distemper work is not large, no color grinder's price list or catalogue is complete unless the list of water colors contains flake white or white lead and Chinese white or zinc white. When the grinder is also a corroder of white lead or when a color-making establishment is connected with the factory where pulp white lead is being constantly used, the most simple way is to take the stiffer portion of such pulped lead and run it through a stone mill until enough of the excess of water has evaporated and the resulting paste is fine and of good consistency. Where this is not feasible, dry white lead is mixed with pure water, requiring about twenty-five pounds or three gallons of water to seventy-five pounds dry lead, resulting in a finished product containing about 80 per cent white lead.
Dry zinc oxide, having great avidity for water, requires almost its own weight of water to form a good mixture to put through the mill, and when finished to be put in glass jars for the trade it consists of about 65 per cent by weight of pigment to 35 per cent of water.
Zinc white ground in water to paste form has many uses in various industries and has been used in that form by calico printers after adding certain mordants. Furniture makers have made use of it for cheap work by adding it to glue size or with casein, thereby saving in the number of paint coats. Also used on white canvas shoes with the necessary binder.