the varnish. The seed-lac varnish is not so injurious to yellow
pigments as it is to the tone of some other pigments, because, being
tinged a reddish yellow, it does little more than intensify or deepen
the tone of the pigment.


GREEN JAPAN GROUNDS.

Green japan grounds are produced by mixing Prussian blue or distilled
verdigris with orpiment, and the effect is said to be extremely
brilliant by applying them on a ground of leaf gold. Any of them may
be used with good seed-lac varnish, for reasons already given. Equal
parts by weight of rosin, precipitated rosinate of copper, and
coal-tar solvent naphtha will give a varnish which, when suitably
thinned and the coats stoved at a heat below 212° F., will give a
green japan second to none as a finishing coat as regards purity of
tone at least. To harden it and render it more elastic half of the
rosin might be replaced by equal weights of a copal soluble in solvent
naphtha and boiled linseed oil, so that the mixture would stand thus:
rosinate of copper 1 lb., rosin 1/2 lb., boiled oil 1/4 lb., hard
resin (copal) 1/4 lb., solvent naphtha 1 lb. When heated to a high
temperature this rosinate of copper varnish yields a magnificent ruby
bronze coloration, especially on glass. Verdigris dissolves in
turpentine, and successful attempts might be made to make a green
japan varnish from it on the lines indicated for rosinate of copper.


ORANGE-COLOURED GROUNDS.

Orange-coloured grounds may be formed by mixing vermilion or red lead