y red on a ground of shining
black.

3. Vases with polychrome decoration.

(a) Vases of various dates with designs in outline or washes in
various colours on white ground (these range from the 6th to the 4th
century B.C.).

(b) Vases of various dates with designs in opaque colour laid over a
ground of shining black (ranging from the primitive period to the
3rd century B.C.).

Of these the second group is by far the largest and most important,
including the majority of the finest specimens of Greek
vase-painting, and the following account will deal mainly with the
technical processes by which the most successful results were
obtained. In both the classes (a) and (b) the colouring is almost
confined to a contrasting of the glossy red ground and shining black.

This black varnish (?) is particularly deep and lustrous, but varies
under different circumstances according to differences of locality, of
manufacture or accidents of production. It is seen in its greatest
perfection in the "Nolan" _amphorae_ of the earlier red-figure period,
at its worst in the Etruscan and Italian imitations of Greek vases.
The gradations of quality may be partly due to the action of heat,
i.e. stoving at a higher or lower temperature. It also varies in
thickness. At present no certainty has been attained as to its
composition--Brongniart's oft-quoted analysis cannot be accepted --nor
has any acid been found to have an effect upon it, though the chemical
action of the earth sometimes causes it to disappear.

The method of its use forms the chief distinction between the
black-figured and red-figured vases, but there is a class of the
former which approaches near in treatment to the latter, the whole
vase being covered with black except a framed panel which is left red
to receive the figures. It is obvious that the transition to merely
leaving the figures red is but a slight one. But in all black-figured
vases the main principle is that the figures are painted in black
silhouette on the red ground, the outlines being first roughly
indicated by a pointed instrument making a faint line. The surface
within these outlines being filled in with black, details of anatomy,
dress, &c., were brought out by incising inner lines with a pointed
tool. After a second baking or perhaps stoving had taken place, the
designs were further enriched by the application of opa