How Printing Systems Make High-Quality Images (2)

Handle white and black in color pictures

The white and black colors in the color picture are not only the important colors in the picture, but also have a black and white tone, which makes the color appear pure and pure. Colorists believe that the world is not absolutely white, nor absolutely black. No matter how bright "white" is, or how dark the "black" is, it has a certain color tendency, but on the concrete picture, there may be exaggerated white and exaggerated black. Therefore, we must pay attention to the black-and-white tones in the color maps when copying. This is an important part of improving the image arts.

At present, most operators only pay attention to the adjustment of color, but ignore the black and white treatment. Therefore, white objects are often treated as white, completely losing the layered texture of white objects; the black objects are handled in darkness, which does not highlight the hierarchical texture of black objects. The solution to this problem is:

1. Improve the understanding of the importance of white and black tones in color pictures

Everyone knows that black and white photographs are more visually pleasing than color photographs because the difference in reflectance between black and white is much larger than any color. According to scientists' determination, the contrast between colors, even the most intense contrast between primary colors or complementary colors, is much weaker than the contrast between black and white. For example, red and green juxtapositions are comparable to black and white juxtapositions, and the former can only reach the latter. 40%, compared with black and white, black and white, the former can only reach 23% of the latter. Compared with black and white, the former is only 19% of the latter. This is why black and white works are sometimes more colorful than black and white. Works come quickly. Therefore, the white and black colors in the color map are processed during the scan, which not only vividly displays the texture of various layers of white and black objects, but also highlights the contrast of light and dark in the visual sense.

2. How to deal with white objects

White is called extreme color in color science. To deal with the white in a color picture, not only can it show the texture characteristics of various white objects, but also white can be eye-catching and give light in the light.

(1) The various white objects in the color photography image are very rich in color tone due to the influence of the light source color. Before processing, it is necessary to fully understand the texture characteristics of various white objects, and then adjust the processing according to different texture characteristics, such as: white Paper, white clouds, white flowers, white silk, white jade, white porcelain, etc., have different texture characteristics and should be different when setting adjustments. The white paper can be handled lightly, while the white porcelain and the white porcelain must show a jade texture and a porcelain texture. For example, some monochromatic porcelain surfaces such as shadow, azure and white glaze are smooth and exquisite. With the texture, the gray level of the highlight area should be maintained during the scanning setup. However, in some of these porcelain albums, the porcelain colors of various white porcelain bowls, white porcelain vases, etc., which are mostly bright and medium-sized, are printed in white, and they are pale like white paper, with only 3% of bright highlights. -5% of the C version, M,
Y version is absolutely net, there are several even the C version are net, completely lost the sense of porcelain.

(2) The white art of fine arts and graphic arts is more characteristic. For example, the oil tanker, gouache, and white are represented by pigments covering it. White is both white and textured. Therefore, when setting, it is necessary to use a three-primary color to form a neutral white, and it is only possible to make the local extremely high light net. In watercolor, white is reflected in the white color of the water color itself. At least one of the watercolors is pure white so that the picture can be bright and clear. Therefore, the local highlight white can be eliminated when setting. Leonardo da Vinci once said: "The whitest part of a painting is as valuable as a precious stone." This means that the white place is very rare in the painting and is a special effect pursued by the painter. Therefore, when setting up the scan, be sure to show it carefully.

(3) The white objects of many printed products often exhibit color cast and dew, because some operators lack consciousness of gray balance. For high-gloss white objects that require a level, set the proportion of gray balance points, such as C5%-6%, M3%-4%, and Y3%-4%. Such as white warm, three-color version of the dot value can also be close to the ratio, but must not lack a color version, otherwise it will be color cast, dew.

3. How to deal with black objects

Black is in the ultraviolet extreme of the spectral band and is called extreme color in terms of color. Processing the black in the color picture not only can express the texture characteristics of various black objects, but also can fully express the heavy sense of the picture and bring out the pure color. Brightly colored.

(a) Black objects in color photography images are often cloudy due to environmental influences. When processing, firstly understand the texture characteristics of various black objects, and then adjust them according to various texture characteristics, such as black steel, black camera, black leather jacket, black sweater, black satin, black hair, etc., with different texture characteristics. It should be different. Such as black steel metal objects, the amount of color can not be lighter, to express its sense of weight, set the black version should be the main outlet, the value of up to 90%, while the three primary colors for the right amount removed, the four-color version of the sum 320% or so. The black leather clothing, it is necessary to show a smooth and thick leather, but also have a leather texture level, set to make full use of the black version to make a hierarchical texture, the color amount of 85% -90%. The tone can be extended to ensure that the middle tone, bright tone levels are rich, and sometimes use Photoshop
The lasso tool pulls out the skin and adjusts it with a black version of the curve. As for black satin and other objects, the main performance of the smooth and delicate texture, scanning the four-color version should be mainly soft and delicate, the contrast should not be too large, the definition should not be too much emphasis.

In actual production, the black color of the object is not pure due to the dark color of the photographic image. Therefore, the application of UCR/UCA function correction, so that the three primary color version to achieve a neutral black effect, and then black-based, so as to achieve the effect of pure black, a good representation of the texture of the black object level.

(2) The dark tone of artistic art pictures is an important part of the image arts. The black color varies greatly due to the different characteristics and styles of various paintings. The scanning settings should be handled differently. For example: Chinese painting is ink. The Lord, pure ink, which ink painting should use the GCR process, do a long tone black version, so that the entire picture layer is rich, black ink can reach 95% -100%. Among them, the color ink painting, whether heavy or light color, should adopt UCR technology, K95%, C70%, MY60%, and the sum of four colors is about 280%. However, some of the traditional Chinese paintings still use the three primary colors for reproduction, while the black version uses the short-cut skeleton technology. This causes ink color casts and delusts and should be improved as soon as possible.

Some inks and gouache paintings are mixed with black and other colors. They are not pure black. Therefore, when setting, they should be mainly composed of three primary colors. C95%, M, Y85-88%, and K70% cannot be used as the black version of a photographic image. So deep. Some of the watercolor's deep darkness is almost a unique taste expressed in pure black. Therefore, it is necessary to reproduce the black version when setting, generally 75% - 80%, while using the UCR method to reduce the amount of ink of the three primary colors, because the color ink watercolor painting is elegant, after the removal of the network value of C65%, M55%, Y55%, The total of four colors is preferably 250%-260%.