Take two slips of cloth about a foot long, and three or four inches wide, wax them as before mentioned, then upon the one slip paint of every one of your entire colours[6] about an inch high over the whole width of the cloth, and with your tints already composed do the same upon the other piece of cloth, according to their order and degradation;[7] mark every tint with a number, such as 1, 2, 3, &c. write down upon a paper every number, and what it is composed of. This done and your colours so applied dry, cut your cloth across all the tints from top to bottom in two equal parts; bring one half of each near the fire, and by melting the wax fix them, the other two halves you keep as they are unfixed.
By rejoining and comparing them together, you may judge what strength every tint will acquire, and by their reciprocal references you will be enabled to alter or imitate, deepen or heighten with certainty, any tint, either before or after the colours are fixed.
In painting be not sparing; the greater body of colours you employ, the better and brighter your work will appear; you may give greater freedom to your pencil, blend and sweeten your colours better than in any other way of painting.
ART. III.
How to paint over or alter any part before the picture has been near the fire.
If the parts of the picture you want to retouch are large and the colouring dry, take a large soft hair pencil, and with water gently moisten those places, or the whole picture if you please, and repaint till your eye is satisfied. You might paint over, or alter any part without moistening, but on a first trial you would not so well see what you are about. While the picture is wet it appears very near what it will be when fixed; when it is dry it looks like a weak dead colouring in oil. You will see enough to judge of the general effect, but none of the tenderer half tints will appear discernable enough to judge of them with precision. In large pictures where the cloth will be required stronger, a picture is kept wet with great ease and security, by moistening it on the back with a large brush as often as there is occasion, for the water will soon soak through the texture and take hold of the colours; there is no danger of disturbing them on the other side with the action of the brush, by reason of the substance of the cloth.
ART. IV.
To fix the colours by melting the wax.
When your picture is finished and dry, have a good clear fire of sea-coals,[8] approach your picture with the painted side towards it, at about two feet distance, let it grow warm by gentle degrees, always approaching nearer, till within a foot distance from the grate, but never closer, holding your picture perpendicularly or a little inclined as you shall find necessary. If the picture is large do one half first, then the other; there is not the least difficulty for any size.
When you perceive by the hue and shining of the painted surface that all is perfectly absorbed; then remove it gradually from the fire as you advanced it, and your picture will be done.