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,8approach 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 advancedit, and your picture will be done.
If you see any place defective for want of a sufficient quantity of wax,9put a little finely scraped wax on the back of that place, then bring only a red hot poker, or some such thing towards it, the wax will immediately settle in its place. If there are many parts so defective, put scrapings of wax there, and bring the whole picture before the fire as above mentioned. There is no danger in bringing the picture tothe fire as often as required, provided you never give it too great a degree of heat; if you do, the wax will raise in bubbles upon the surface, and your picture will look rough and uneven.
Advance your picture never too hasty, nor retire it too quickly; if you do the former, the sudden action of the fire might disturb some of the colours; if the latter, the wax will not retire enough within the texture of the cloth, consequently lye too much above the colours and look glaring. If you perceive any such glaring spots or places upon your picture, or (inother words) parts that appear varnished like, and that appearance should proceed from too great a quantity of wax, paint those places over on the back with whitening, or any one of your other colours, and when dry bring the picture near the fire, as above mentioned, and those colours or whitening will imbibe the overplus of the wax. Repeat that if required.