DRIERS

Driers are substances employed to facilitate the drying of paints. The driers most commonly employed are sugar of lead, litharge, and white copperas. Either of these when well ground, and mixed in small proportion with paints, very materially hastens their drying. Indeed, some colours will not dry without them. Red lead is also well adapted for a drying agent, and in cases where its colour does not preclude it, is much used. The best drier is sugar of lead. Its cost, however, is somewhat higher than that of the other driers. It is important to bear in mind that in the finishing coats of delicate colours driers are not generally had recourse to, as they have a slight tendency to injure the colour. A drying property may be imparted to linseed oil by boiling it with drying substances; it then becomes a very useful vehicle for some purposes. See Oils, Drying .