The color processing technology of gravure image belongs to the pre-press basic knowledge of gravure printing. When preparing for the pre-preparation work of gravure printing, the following four essentials should be mastered when adjusting defects such as insufficient local saturation.

1. Adding color and subtracting color should not be excessive

- The basic color plus color should not be too large. To maintain the level in the basic color, the level should not be leveled due to excessive coloring.

- The amount of color correction should not be too large. To maintain the relationship between light and shade and light and shadow in color, the color can be simplified due to excessive color correction.

2. Maintain the relationship between the amount of color and the amount of light

- When adjusting a certain color, the color quantity of the bright adjustment part cannot exceed the color quantity of the middle adjustment part, and the color quantity of the middle adjustment part cannot exceed the color quantity of the dark adjustment part, and the color quantity and the light quantity level of the color are to be maintained. Light and dark, deep and shallow relationship. Now some prints have adjusted the color of the bright part too deep and too heavy, and the color of the dark part has been processed too brightly, losing the normal relationship of color, giving people an uncomfortable feeling.

3. Master the law of spatial distance variation of color

- From the color point of view, our line of sight is affected by the space and atmosphere medium, and objects of different distances will change differently in shape and color. The object's near-large and small is the principle of space perspective, while the object's closeness is clear, the far-field is blurred, the color perception is close to the strong, and the far side is weak, which is the result of the color space perspective. Therefore, when adjusting a certain color, it is necessary to grasp the change law of the color expression space distance, near warm, far cold; near pure, far gray; near bright, far blurred, near contrast strong, far The contrast is weak. 

4.Master the law of color change. In the natural scenes of color photography, we find that the color of the object's light surface is inseparable from the change of the light and color of the light source color, and the color of the dark surface is closely related to the change of the surrounding environment. Therefore, when color adjustment is performed, it is necessary to grasp the law of change of color and warmth. At the same time, pay attention to the following two issues.

- There are three parts in the light-receiving surface: high light, bright surface and medium-tone surface. The hue of the bright surface is mainly the combination of light source color and intrinsic color. The color of the light and cold is transferred by the warm and cold of the light source color; the color of the highlight part is generally It is the hue and chromaticity of the light source color; the light received by the object in the object image is not direct light, but side light, which is more complicated and rich in hue and color. The hue is the complementary color, natural color and ambient color of the light source. In general, the color is dominated by the inherent color.

- The hue of the object is dark, mainly the combination of the ambient color and the intrinsic hue. The warmth and warmth of the hue is shifted by the warmth and warmth of the ambient color, and the color of the dark part always has the complementary color tendency of the light source color. Therefore, it should be noted that the dark color is not the deepening and darkening of the inherent color. The relationship between the cold and warm colors in the photographic picture can only be satisfactorily achieved by the standardized scanning color separation method using the restored original.