better means of expression.
In a way, almost every painter of early times was an inventor, and had
to be, because for a long time the methods and tools of painting were
absurdly insufficient. Every man who succeeded had discovered some new
way of grinding and mixing colours, of preparing the surface on which he
worked, of using the brush and the knife, and of fixing the finished
picture by means of varnishes. The question of what painters call the
vehicle for colour was always of immense importance. Long before Giotto
began to work there seem to have been two common ways of painting,
namely, in fresco, with water-colours, and on prepared surfaces by means
of wax mixed with some sort of oil.

In fresco painting, the mason, or the plasterer, works with the painter.
A surface as large as the artist expects to use during a few hours is
covered with fresh stucco by the mason, and thoroughly smoothed with a
small trowel. Stucco, as used in Italy, is a mixture of slaked lime and
white marble dust, or very fine sand which has been thoroughly sifted.
If stained to resemble coloured or veined marbles, and immediately
ironed till it is dry with hot smooth irons, the surface of the mass is
hardened and polished to such a degree that it is almost impossible to
distinguish it from real marble without breaking into it. Waxing gives
it a still higher polish. But if water-colours are used for painting a
picture upon it, and if the colours are laid on while the stucco is
still damp, they unite with the lime, and slowly dry to a surface which
is durable, but neither so hard nor so polished as that produced when
the stucco is ironed. The principal conditions are that the stucco must
be moist, the wall behind it absolutely dry and the colours very thin
and flowing. Should the artist not cover all that has been prepared for
his day's work, the remainder has to be broken out again and laid on
fresh the next day. It is now admitted that the wall-paintings of the
ancients were executed in this way. As it was impossible for the artist
at any time to have the whole surface of the freshly stuccoed wall at
his disposal in order to draw his picture before painting it, he either
drew the design in red upon the rough dry plaster, and then had the
stucco laid over it in bits, or else he made a cartoon drawing of the
work in its full size. The outlines were then generally pricked out with
a stout pin, and the cartoon cut up into pieces of convenient
dim