التصوير بالوان التمبرا أو الجواش ٣_a , من كتاب تكنولوجيا التصوير , د.م محمد حماد

Some photographers prefer, before starting painting with color on surfaces prepared with gesso, to paint the entire surface of the painting with a layer of egg yolk and water in a ratio of 1:1 or 2:1 in order to pave the colors with a homogeneous surface that increases the flexibility of using the color by brushing on the surface of the painting, which makes it easier for the photographer to work according to the method he chooses. The ancient Egyptian painter followed him, as we have already mentioned, and they do not see any fear of the effect of the color of the egg yolk on the surface of the painting, as it quickly wears off, and after it dries, the artist can start the coloring process. - (D) Wax tempera was used by artists of the Middle Ages. And with those colors they painted some of their works that still remain until now, and it was thought that they were works painted with oil colors. Tempera wax colors are usually prepared as follows: 1 gram of wax crumbled into small pieces 100 grams of pure water 100 grams of pure glycerin These quantities are mixed and heated over a fire at a suitable temperature. Quick movement... Thus, we find that the wax has melted in the liquid and formed an emulsion that can be kept for a long time in a closed bottle to be ready to make the wax colors after mixing it with the required color powders. It is advisable to put a layer of it on the surface to be painted on before starting to paint over it... As for the method of working with this type of tempera, it is similar to the method of oil painting. 150 grams of hydrated lime, 100 grams of Abu Noum oil or walnut oil, 300 grams of white Spain (calcium carbonate). 08. . It works as an emulsion to which color powders can be added. 0 . (f) Boiled linseed oil tempera and its colors are prepared according to the following formula: 100 grams of milk, 1 gram of Venice resin, 20 grams of boiled linseed oil • one egg yolk • a drop of fennic acid Y. . . . Resina di Venezia Mix the resin and the oil, then add the egg yolk and stir the mixture well with a teaspoon, then add the milk little by little with stirring, then add the acid

The technician uses a drop by drop to preserve the emulsion for a long time until it is mixed with the powders of colors required to be painted with. It can be preserved in glassware (g) Tempera of wheat flour, prepared with the following ingredients: 1 part fresh egg yolk 3 parts boiled linseed oil •. 15 parts of wheat flour dissolved in water in the form of a thick liquid. The egg yolk is mixed with the oil and beaten well, and the flour mixed with water is added to it, so the resulting emulsion forms and becomes ready to add color to be used in tempera paint. Commonly used in the past: - Gum Arabic, Venetian turpentine, vinegar, a quantity of soap and an egg (yolk and white) - An egg yolk, an amount of soap and water, Venetian turpentine, oil varnish and vinegar • An egg, fish glue, vinegar, soap and oil varnish • (i) Mastic and egg tempera, to be according to composition Next: A volume of beaten egg (yolk and white) A volume of mastic varnish - A volume of boiled linseed oil A volume of pure water The mixture is beaten vigorously for a long time and some drops of emulsified vinegar are added to it to which powder of the required colors is added (j) Tempera de Chirico It was named after its owner who came up with this favorite formula after a long search. It consists of: 1 beaten egg (yolk and white) 2 teaspoons of Abu Noum oil (poppy). 1 teaspoon of volatile turpentine • 1 teaspoon of pure glycerin 1 teaspoon of white wine vinegar • 1 teaspoon of purified water Put all in a small bottle and shake well until it forms a smooth emulsion

From these different compositions and others, we see that the ancient artists searched a lot to improve the composition of the colors used in tempera in accordance with their thinking, experiences, and materials that could be available to them, but the basic types that were used since ancient times and are still used until now are the first three types, which are gum and tempera. Glue and egg white tempera can be mixed with powdered colors required for painting. It is advisable to paint the surface on which to be photographed with the same material before the start of the photographic process. 3- The pigments that are included in the composition of tempera are well-washed colors. All powdered colors can be used, noting that fine atoms like clay colors are used with all types. As for the colors whose atoms are inaccurate, they can only be used with strong media such as glue. Types of white can be used in the colors of tempera, namely: (a) zinc white (b) silver white (c) calcio Spain white We note that Spain white is bitter from calcium carbonate Carbonato di and it is called by many names, even if it has the same composition, so it is said, for example, white Bianco di Champagne, Bianco di Meudon white, Bianco di Bougival white, Biancone, and all these names belong to one compound. It is safe to use it as a white color in tempera colors. As for silver white, which we recommend not to use, it is absolutely forbidden to use it in wall tempera colors because it is a toxic color and causes disease. Known as lead paralysis 7 . Bianco di Zinco Bianco d'argento Bianco di Spagnia No. As for the rest of the colors of yellow, red, blue and their derivatives, we must always make sure when using them that they are well cleaned and as accurate as possible. We also notice that the colors that we create are not to a great degree of liquidity, and that they are thick in texture, but rather have a medium texture, which helps the photographer to perform his work with ease and freedom. 4- The brushes used in tempera photography are the same types of brushes that are used in oil photography and must Wash it well with water after using it. It is preferable to wash the brushes with a solution of water and alum if they are going to be left for a long time. E- The color sheet (pallet), which is usually made of one piece like the oil color sheet, except that several concavities are made around it to place the colors, as its colors are not coherent like oil colors (Fig. 25). • The color sheet can be made of strong wood or metal coated with a paint of Chinese or plastic

Advantages and disadvantages: Among the virtues and advantages of tempera colors in which egg white is used as a medium are the following: (1) The color does not yellow or darken with the passage of time and the aging of the painting, as usually happens in oil painting... On the contrary, the colors here are brighter the more the ground of the painting is dried. Gesso is usually used as a ground for tempera photography. (b) The second feature here is the stability of the colors to a large degree, so they do not dissolve easily in water, especially after aging. • (c) Because of the technical method used in tempera photography, the colors do not overlap with each other. We see that the colors and lines are clear and specific. • For these reasons, Many old artists used to prefer this method of painting since the Renaissance ... and even now, because if all care was taken in the performance of painting and coloring, the tempera would have surpassed oil painting in its splendor. The following: (1) It exhausts the photographer in preparing the medium with the color each time, as it cannot be preserved for a long time. · (B) The work requires great care in performance. (c) It is difficult to correct or modify the color, unlike oil painting.