To adopt and practise in earnest any new system without sufficient
trials and proofs of its merit, may be called going wilfully
astray.--To avoid deceiving myself in the new system before us, I,
after having been convinced of its advantageous practicability, set
about to ascertain the other great point, the stability of the colours;
for this end, and to know more exactly how much every colour would vary
from its original hue in a certain space of time, as well in regard
to the same system as in opposition to oil-colours, I proceeded as
follows.
_Experiment the first and principal, 1757._
I had all the colours used in oil painting, mentioned in the foregoing
list, carefully ground with water, at Mr. Sandys’s, colour-merchant,
and from those colours I composed ninety various and sensibly differing
tints, for flesh, drapery and landscape; of each tint I had a quantity
of a two ounce gallipot full, tempered with water; so I left them
well screened from dust till they were become dry again; then I
divided each mass of tint in four equal parts; two of each I set by
for the comparative use, the other two parts of each I employed in the
following manner.
One part of each I tempered again with water, and painted with it over
a space of cloth of six inches wide and two inches high, the tints
close to each other, in the manner of copper-plate, _page 58_, and the
cloth waxed as directed _Art. IV. page 26_. The same I did with the
entire and unmixed colours.
The other parts of each tint I tempered with the finest nut-oil
according to custom, and painted-over with them such another space of
six inches by two, as the former, upon oil-cloth. The same I did with
the entire colours, and set them by to dry; when dry, I brought the
encaustic tints near the fire, and by melting the wax fixed them.
My tints thus ready, I cut each piece of cloth, encaustic and
oil-tints, in five equal parts, and disposed of a piece of each in the
following manner.
1. One piece of each I exposed in the open air to all the injuries of
sun, dew, wind and rain.