What are the characteristics and production methods of oil base?
Oil base has the longest history and is the most popular. It is mainly used for canvas, but also for wood boards and so on. The oil base is basically composed of rubber base and oil layer. The traditional base material is animal skin glue (mostly rabbit skin), and the base coating is oil coating (linseed oil 15g + turpentine oil 15g + lead white 25g). The production method is: the skin glue with water heating melting, while the glue is warm when the canvas, cool dry and then coated with white oil substrate paint. The oil in the bottom coating should be as little as possible to ensure that the subsequent pigmentation layer is firm. Apply a layer of bottom paint, the canvas can be used, but if you need a smoother surface, the canvas will be wiped flat, so the bottom paint to be painted two to three times. The canvas with a good oil base needs to be placed for several months before it can be used, and the longer the time, the better, the ideal time is half a year. https://painting-portrait.com/
The oil bottom is a weak absorbent bottom, with a fine surface, strong elasticity, impact resistance and moisture resistance. The disadvantage is the lack of permeability, no glial bottom coloring force is strong, will lose elasticity as a result of aging, color layer because of embrittlement and cracking, and even fall off. In addition, the oil base is easy to turn yellow.
Since the production of synthetic glue, modern painters often use white latex as base glue. Method is: latex and water diluted on the canvas after coating two to three times, and then with latex and a small amount of water, add Lide powder (can also be added in the inside of the toning oil), stir evenly after coating or scraping on the canvas. After WAITING FOR DRY, WITH OIL PAINTING PIGMENT (USUALLY WITH WHITE, ALSO CAN ADD LESS XU QUNQING, EARTH RED AND SO ON TO ADJUST GRAY) A THIN GROUND BRUSH CAN BE.
Professor Claude Yvier used to teach classical painting techniques in China. He used the system method of the classical master. The specific methods are as follows:
Step 1: Scrape the bottom. The taut canvas is trimmed slightly with sandpaper or pumice stone, and then coated with rabbit skin glue (the ratio of glue and water is 7 to 10∶100). The film is then broken up and soaked in cold water for five to six hours to allow it to rise and then melted by stewed water. Or soak with a little cold water first, wait for it to rise and become soft, then inject hot water and stir to completely dissolve. When the glue is still warm (about 17℃), you can apply and scrape the canvas. When the canvas is flat, pour the glue first, and scrape the glue onto the canvas with a big scraper. After scraping the whole canvas, remove or flatten the threads and knots while it is still dry. https://painting-portrait.com/
Step 2: Paint a red background. Grind ochre red powder (iron oxide red) with walnut oil boiled with yellow lead oxide (lead oxide) to the appropriate thick thickness, on the canvas coated with glue, scrape the pigment with a scraper, cool dry and then polish the pumice stone again, so that the surface of the canvas is smooth and uniform.
Step 3: Paint a gray base. Use one part walnut oil to one part linseed oil, grind lead powder and carbon black toner. Use a stiff brush to apply the pale grey to the canvas. The ratio of black and white toner is arbitrary. The gray bottom should be painted as thin as possible, so that the canvas bottom is not easy to crack. Do not brush only once, lest the red bottom emerge, and do not cover the fabric of the linen. You can scrape a layer of grey base with a scraper first, and then apply a second layer with a stiff bristle brush after drying, and then wipe off the marks with a badger brush. Can be slightly added to the earth red pigment to become a light gray red.https://painting-portrait.com/
