Analysis of the hottest transmission manuscript I

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Transmission manuscript analysis (I)

transmission originals include natural color positives, natural color negatives and second originals

first, natural color positive

natural color positive, also known as color reversal film, accounts for a large proportion in the current plate making draft. With the vigorous development of China's industry, it will be more used in the future

1. Characteristics of natural color positive films

there are two kinds of natural color positive films. One is the reverse film, which is made by bleaching and fixing after secondary exposure and secondary development. The edges are thick black, which is commonly used to copy the original; The other is a copy positive film amplified from a color negative film. The edges of the four sides are transparent and the particles are thicker, especially on the Yellow separation negative film. Natural color positive film is a kind of color multilayer photosensitive material. Its film base is coated with multilayer emulsions (upper, middle and lower). Each photosensitive layer emulsion is composed of silver halide, gelatin pigment and corresponding color coupling agent. Color coupling agent is a colorless and transparent organic compound, which can make the photosensitive emulsion form the complementary color of the primary color after exposure and development. Its top layer is blue sensitive light, showing yellow; The middle layer of green light, showing magenta; The lower layer is to feel the red light, showing cyan. In order to avoid the effect of blue light on the emulsion in the middle and lower layers, a yellow filter layer is applied between the upper and lower layers. Therefore, it becomes a color photo with the same color as the original after secondary exposure and secondary development. As shown in figure 8-2-1

the contrast coefficient of the photosensitive performance of natural color positive films is large, and the tolerance is smaller than that of ordinary photosensitive films, so the contrast is particularly strong. At the same time, because it is a transmission manuscript, the high-profile part has strong light transmission, and the dark part is due to. The layer emulsion has thick pigment and little luminous flux. Therefore, the maximum contrast can reach more than 3.0, which is normally about 2.0. The perspective and texture of the objects it takes are very strong, the colors are bright and dazzling, the light and dark levels are rich, and the particles are exquisite and lifelike, which expresses the real effect. However, due to the exposure time, color temperature deviation, improper washing and other factors during photography, the reduction of the three primary color emulsion is unbalanced, and there are often purple, green, tea, thin color, too stuffy and other phenomena

the image recorded during the shooting of natural color reversal film is negative. As shown in figure (8-2-2), straight line AB is the original scene, a is the high-profile part, and B is the dark part. The negative image of silver particles obtained by the first black-and-white development after shooting is an ab density curve, which exists in shoulder a and toe B. the shorter these two parts are, the straighter the straight part will be, and the higher the quality of the inversion film

since the black-and-white negative image developed for the first time exists in the shoulders and toes, the remaining undeveloped silver halide emulsion is obtained after secondary exposure, color display and bleaching. The color positive image a 'B' also exists in the shoulders and toes. From figure 8-2-2, it can be seen that the natural color inversion film is just like a 'B' density curve, which is different from the original AB, the high-profile level is compressed and flattened, the dark level is parallel, and the quality of the inversion film is worse, The greater the difference between the light and shade of the original scene, or the greater the error of shooting and washing

therefore, attention should be paid to the adjustment and compensation of tones during plate making and copying

2. Requirements for the production of natural color positive plates

natural color positive original copy. At present, direct addition process and electrical separation process are mostly used, and the effect is ideal. Due to the small size, high magnification, strong contrast and long exposure time of the original of natural color positive film, the lines drawn on the original become thick and paste after color separation, resulting in the malady of incorrect chromatic registration. Therefore, when copying, use black film to make the specification frame of the original, and the lines on the original can be clearly penetrated

the original of natural color positive is the one with the most electrographic plate making at present. The electrographic reproduction should grasp the following key points according to the special load of natural color positive:

(1) master the tone of each original, that is, whether the scenery of the original is dominated by cold tone or warm tone, which is usually also known as boundary lubrication. And note that some works are the tones that the author particularly pursues, which cannot be regarded as partial colors. If the tone of the picture is not thoroughly analyzed and mastered, it will cause failure in reproduction

(2) highlighting light sensitive lines is an important means of photography creation and will inevitably squeeze some traditional automotive materials. Photography uses light not only to depict the shape and color of the subject, but also to shape character images, set off the atmosphere and convey feelings. Therefore, special attention should be paid to highlight the sense of light when copying, so as to maintain a certain contrast in the picture. The light should be bright, and the dark should be dark. All kinds of light spots in small areas should be unique. When talking about mediation, there should be a certain contrast of rising and falling through the precision lead screw sub belt beam after being slowed down by the deceleration system, and the light should focus on the center of the picture. Only when the picture has a sense of light can it have a sense of distance, perspective and three-dimensional sense. Otherwise, the picture will be gray and dull and lose the characteristics of photography art. Of course, some photographic manuscripts have little contrast but strong artistry, which is another matter

(3) it is necessary to grasp the characteristics of natural color positive films such as true colors, natural changes, thick and bright colors. Due to the high color saturation of natural color positive films, and the influence of ink, paper and other properties on printed products, the color of printed products is darker than the color of actual scenery, and there is a large gap between the two. Therefore, the color correction range of electrical separation is one level higher than the standard color correction range, which can make up for some deficiencies. The original with normal color should be faithful to the original color. For the originals that are biased or too dull and thin, the color tones should be processed emotionally and reasonably, and the artistic processing should be given to the colors of the real scenery. For example, for an all-round thin manuscript, the color amount must be increased comprehensively. A group of white sheep or geese occupy the main body of the picture, and the background sky is light, which can deepen the blue sky and highlight the theme. As long as there are these ideas and intentions in the adjustment, there are still ways to do it in technology

(4) master the sharpness of the image. Natural color positive films have high sharpness, which is the key to determine the reproduction quality. Therefore, we must make good use of the fine level adjustment function of the electric extension. We should select and set appropriate light holes and fine level emphasis according to the characteristics of various originals, the sharpness and magnification of color films, etc. The smooth and delicate picture is the premise of high-quality printing. Special attention should be paid to the smooth face and skin color of women and children, the color of large flat blue sky, and the talkative and uniform background. It is necessary to prevent coarse particles and pay attention to the quality

(5) for color positive plate making with high density and high contrast or high density and low contrast, attention should be paid to the reproduction of high, medium and low levels of image and hue. For example, the level and tone of a certain tone are lost, causing the picture to be dull. The correction amount of color positive film with color deviation should not be too much, so as to avoid excessive loss of high-key and sub high-key levels

generally speaking, natural color positive reproduction also requires that the color tones on the screen are appropriate, the scenery atmosphere is natural, the object texture is strong, and the perspective feeling is far-reaching. Because these are the basis for evaluating product quality

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