At the same time a greater distinctness was given to the scenes represented upon the sculptured slabs, the color being judiciously applied to disentangle human from animal figures, dress from flesh, or human figures from one another.
The colors actually found upon the bas-reliefs are four only--red, blue, black, and white.

The red is a good bright tint, far exceeding in brilliancy that of Egypt.

On the sculptures of Khorsabad it approaches to vermilion, while on those of Nimrud it inclines to a crimson or a lake tint.

It is found alternating with the natural stone on the royal parasol and mitre; with blue on the crests of helmets, the trappings of horses, on flowers, sandals, and on fillets; and besides, it occurs, unaccompanied by any other color, on the stems and branches of trees, on the claws of birds, the shafts of spears and arrows, bows, belts, fillets, quivers, maces, reins, sandals, flowers, and the fringe of dresses.

It is uncertain whence the coloring matter was derived; perhaps the substance used was the suboxide of copper, with which the Assyrians are known to have colored their red glass.
The blue of the Assyrian monuments is an oxide of copper, sometimes containing also a trace of lead.