The Art of Painting in Oil, and in Fresco; Being a History of the Various Processes and Materials Employed, from Its Discovery (Paperback)

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: arise from the action of the fire to which the seed is exposed in extracting the oil from it. This colour, in fact, proceeds from the pellicle which covers the grains, and which contains a strong colouring matter soluble in oil. Linseed oil, cold drawn, as used in medicine, is equally coloured with the other sort; but, like that of wax, this colour is carried off by exposure to the sun. Linseed oil is extensively employed in the manufacture of hard varnish, because it is of a more drying nature, and preserves its transparency better than the other oils. NUT OIL. When cold drawn, this oil has very little colour, and the common sort has even a less tinge than oil of linseed. Some give it a preference for pictures much exposed to the air; besides, it does not become so dark as linseed oil by the action of the oxide of lead. OLIVETTE OR POPPY OIL. This is the most colourless, but the least drying, of the three oils. As the poppy plant is much cultivated in Flanders, we may suppose that this oil has obtained a preference in the school of the Low Countries, where the poppy is in many places called the olivette. Although these oils have a natural tendency to dry, yet this quality is not sufficiently strong to overcome the action of some colours which retard it in various degrees;?for instance, the lakes, bone or ivory black, and particularly the bituminous earths. But experience, from which this information is derived, has also taught us, that there is a drying power in some metallic oxides, which facilitates the preparation of oils, in a manner that quite overcomes their original difficulty in drying. TO PREPARE DRYING OIL. From the tendency that several of the oxides and metallized salts have to unite with oils, and thus to render them more drying, has resulted a ...