Paint and varnish

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1917 edition. Excerpt: ...stain. A dry soluble form is marketed as "sap brown." Vandyke brown ground in oil and thinned with turpentine makes a good walnut oil stain which is not too transparent and is decidedly permanent. Its one objectionable feature is its very strong retardation of the drying of linseed oil. The color of Vandyke brown, may also be obtained by using burnt umber, drop black, and Prussian blue, producing a color that is permanent, but lacking the transparency of true Vandyke brown. G. BLUE PIGMENTS (a) Prussian Blue.--Prussian blue is formed by precipitating potassium ferrocyanide with ferrous sulphate and oxidizing the resulting pale bluish precipitate into the characteristic dark blue of this pigment. There are many closely related varieties depending on details of treatment in their production. Prussian blue is a transparent pigment of great strength, i pound giving to a ton of white lead a decided sky-blue tint. It is fairly permanent except in contact with alkalies or lime, which decolorize it rapidly. With white pigments it should give a decided blue tint, not purplish or muddy. Being very fine in texture it does not settle in the vehicle, and hence is used by implement manufacturers as a dipping paint for polished steel parts. (b) Ultramarine Blue.--Ultramarine was formerly obtained from the mineral lapis lazuli, a semiprecious stone. It is now made artificially in large quantities and at low cost by heating together clay, silica, sodium carbonate, sodium sulphate, charcoal, rosin, and sulphur and treating the product by rather intricate processes of grinding, roasting and washing. It is bright but of low color strength, varying from a pure blue to colors bordering on green, which latter are called "green ultramarine."...