اللون والضوء في التصوير ، من كتاب تكنولوجيا التصوير من ص ١٥ - ١٨

Color and light in photography:

In addition to those definitions previously explained, it is important for us here to mention a word about colors, although we will mention them - as structures used in photography - when talking about each type of photography. To be aware of the theory of light and colors, and its broad outlines, so that he can benefit from it when he needs it in his practical life.. because this helps the artist to understand his work.. although he always prefers to resort to his sensitive sense and quick intuition to define colors. It is more suitable than others to obtain light in the simplest form, or in its most complex form, because the artist who is well-established in his art is always sensitive to color. Although knowing the natural laws of light and colors is still a matter of great benefit to overcome the obstacles and overcome the obstacles in a better way, and those obstacles can stand in the way of the photographer in his work every day. From that, we note that the bundle of solar rays or white light falling on a triangular prism of crystal is dispersed in the colors of the spectrum and results in infinite degrees of colors that start from red to yellow, and from green to blue to dark blue, provided that if an aggregation of each The colors of the spectrum at one point will be formed again by white light... This was proven by Sir Isaac Newton. As for the colors of the bodies, they are determined by the process of absorption of some radiations and refraction of others, and therefore we see the body of yellow color as well, as it works to refract the yellow radiations on the eye and absorbs other radiations. Exact proportions determine the white light. And from the union of only three colors in all possible ways, all the colors that appear before us in nature can be obtained, and these three colors are called the primary, primary, or primary colors. In photography, we can easily prove that two colors (the original color and its complementary color) - one opposite the other in Spectrum magazine (Fig. 1) - determine the color brown, as is the case when mixing blue with orange, for example, or violet with yellow, or green with red, and so on. on. The first of the primary colors is yellow, a color of great reflexive power, which is found in most natural flowers (usually symbolizing the sun) and produces from it an infinite number of hues and shades. If it is mixed with red, it produces orange, which is complementary to blue. If it is mixed with blue, it produces another secondary color, which is green, which is complementary to red. The second of the primary colors is red, and it is located between light yellow, which is a color that is positive in appearance, and follows yellow in this order. If it is added to any of the other colors, it will give it a certain degree of heat, equal to blue
What is added to it. The red color is a color that has double strength and great compatibility with the yellow color more than blue, because in the first case it is a hot color with a high temperature, although this temperature is weak with the blue color. We notice that red appears more clearly than or was in the middle of black, although it is a positive color in both cases. The third of the primary colors is blue, and it has an obelisk close to shades and is associated with the coldness of the color and its compounds derived from it. It is a strong color in intense light, and it appears with a lighter effect when the light decreases, in relation to its absorption of light... Therefore, it deceives the photographer who paints on the light because of what appears in it of an unreal appearance. It also appears clearly above the white ground, and the degree of its effect on vision depends on the amount of light falling on it and its distance from sight, and we notice that sunlight increases the glow of the appearance of the orange color, as well as the glow of all the colors that this color is included in. As for the second secondary color, it is green, and it stands in the middle of the scale of natural colors, attributed to shade and light. It is considered a full shade color when it is composed of three parts of yellow and eight parts of blue. It is a beautiful natural color and has a calming effect on human nerves. Violet is the third of the secondary colors, and it is the coldest of the three colors and the closest shade to black. the light

It is said about the color that it is pure or pure when it is not mixed with white light, and that it is dense when it is very bright, and saturated when it is pure and dense at the same time. In photography, the group of colors that are obtained by mixing them with each other is called the formula, while the intensity and degree of the color are determined. For example, the green color to which white is added has a light degree, while it has a darker degree if blue is added to it. Discrimination was often made in photography. Between hot dyes, cold dyes and neutral dyes. As for the first type - that is, of the hot colors - it comes in the forefront of red, golden yellow, orange, natural and burnt sienna. As for the cold colors, they are on the contrary, and are predominantly found in blue, green and violet colors. As for the neutral colors, they are nothing but the gray colors that are obtained by mixing white with black. Cool colors are called penetrating or exclusionary colors, while hot colors and dyes are called close colors. And if we look carefully at one point and then shift our gaze to another color, the latter appears to have undergone a change in its color due to the effect of its complement. It is the complementary color to blue, and this optical phenomenon is called “contrast successive.” But if we look closely at two different colors that are close together at the same time, we quickly notice that each color appears to have changed due to the mutual influence of each color on the other..meaning that the complement of the first color changes the true value of the other..and vice versa. This phenomenon is called “double contrast.” For these reasons, we find that it often happens when drawing an external view of nature that the eye, after being affected by the dominant color, sees all the other visible colors that have undergone a change. Therefore, an error may occur in the recording drawing of nature. This is by exaggerating the degree of coloring the painting with a specific color. In order to avoid such stress, the only thing that can be done is to rest the eye by stopping work and resuming it after that. Near complementary colors can be bright by acquiring special vibrations, as is the case with red next to green, violet next to yellow, orange next to blue, etc. While similar colors placed next to each other, such as green with greenish yellow, red with orange, and violet with blue, we see them as dull and dull in particular. Black absorbs all the colors of the spectrum and does not refract any of them. Therefore, if we put ona on a black background, it appears to us more intense and brilliant, while the black color can also be affected by the color associated with it to some extent, especially the pure colors that tend to change it with their complementary colors. On the contrary, the colors above the white color appear more dull than their natural state. And the great artist Leonardo da Vinci says in his book on photography: “The white thing appears whiter when it is in a darker field..and it appears darker when it is in awhiterfield
This is because color in photography is a relative matter, meaning that color always appears different according to the colors that are consistent with it. Da Vinci also mentions: “There is among the colors that are equal in perfection, a color that outweighs the rest of the colors, provided that it is viewed in conjunction with the color that completely contradicts it, such as the dull color with red, and the black color with white, although neither this nor that is considered an independent color.” The same applies to blue with yellow and green with red, because each color is distinguished by its opposite more than its counterpart, such as the dark in the light and the light in the dark. Black clothes show bodies whiter than they really are, and white clothes show dark bodies, while yellow clothes show colored ones, but red clothes show them as pale.” Shadows are also subject to the influence of the complementary color of the body from which these shadows emanate. This is confirmed by Leonardo when he said, “The color of the shadow of any color is always included in the color of its subject, and the degree of its color differs from its proximity or distance from the color of its shadow, as well as the degree of its light.” He also says, “Often, the shadows of shady objects are not accompanied by the colors of light, and the shadows are greenish and the lights are reddish, as long as the body is of a similar color.” And he also said, “I often saw a white body with red lights and shadows tending to blue, and this is what happens in the snowy mountains when the sun is a blazing fire.” Then he said, “The shade of the white color under the sun and the air has its shades that tend to blue, and this results because white is not a color in itself, but rather any of the colors.” Radiation is a natural phenomenon that we often find in landscapes, and the luminous source is stronger than it, and the spread of rays appears more extensive, and the light body - placed on a dark background - appears much larger and more luminous than it is in reality (Fig. 2). The same thing between two bodies of one color, dimensions and equal distance, but the degree of their illumination differs ... The more luminous body appears larger than the other less luminous body, and the color of the bodies for the same phenomenon appears somewhat blurred when placed over a clearer background, as is the case for For leaves and small twigs under the dome of the sky. ...