[106-107] The best method of preparing the ground is the following: -Over a well-stretched, bleached or unbleached, even threaded canvas, spread a thin layer of boiled flour and pipe clay. Let this dry perfectly, and repeat the operation till the canvas shows no more open pores. If this layer is about the consistence of liquid honey, the canvas will only require to be spread three or at most four times with it. The best sign is when the canvas is no longer porous. For too much of the mixture spread over the canvas would cause it to crack on the slightest pressure. That the whole texture should show through this mode of priming is very probable. Whosoever is frightened at this circumstance can buy very fine canvas. After these three spreadings, prepare an oil-colour of white lead and oil of turpentine, of the same consistence as the house-painter uses for his first coat of paint; spread the whole canvas over with it quickly, as clean and smoothly as possible, and let it go 'quite dry'['italics'], so that any roughness may afterwards be easily rubbed off with pumice-stone. [cont'd p.6] ,The dust of the pumice must be washed off. This canvas must be spread once more with white oil-colour, very even, and directly touched with a badger hair pencil. This oil-colour, however, must not be mixed with any more turpentine, nor must it be so thin as on the first application, as its purpose now is to cover: when this coat has been touched, sift over it some fine flour, so that all glittering spots may be covered. Let the flour remain on a few minutes, so that it may combine with the oil, then lift the canvas, shake off gently the superfluous flour, place the canvas on an easel, and with a squirrel's hair brush dust off very lightly any remaining flour, not incorporated with the oil, and then let this canvas dry well in the sun before painting on it. [105-106] If it is laid down as a principle to use little oil in painting, the ground to painted on must have little oil; for the ground also belongs to the picture. The old masters knew this well; they often made use of their grounds in such a way, that where the tone allowed it, they sometimes did not in certain parts even over-paint the ground at all. A good ground for oil-painting should have the properties of paper soaked in glue. A good ground should hold the colour laid on, that is, it ought to imbibe the oil somewhat, and only a 'thin' ground can do that. The colours must be able to evaporate from the back and the surface. This is impossible on a thick ground, as the after-darkening of the colour must follow upon the frequently quick over-painting. [108] Such a preparation of the ground may be applied not only to canvas but to wood. There is no fear of its cracking or tearing. [109] In order to convince myself of the durability of such a ground, I painted a picture on one of this description[p.7] [109] some twenty years ago, which, though exposed to the action of the air ever since, is yet in complete preservation.,Painting on such a ground has this particular advantage, that the oil can entirely penetrate the under-painting, which becomes thereby a 'thin' one, an essential for a good under-painting. A thick greasy colour can only take effect properly upon a thin ground.,If it is wished to paint a picture quickly without having any of the above primed canvas, we can immediately under-paint with oil upon a ground consisting of three or four spreadings of this mixture. There will be a very thin ground, which can, without prejudice, be over-painted and finished in a few days. Such a picture will never darken, for the oil will evaporate on both sides.,,