Application of Kodak Approval XP in Color Digital Proofing (I)

Kodra Poly's Approva XP is a high-end digital proofing device in the printing industry. It entered the Chinese market in 2003 and now has many users, mainly in East China and South China. Shanghai Shuke Image (Shanghai) Co., Ltd. was the first company to introduce this equipment. The equipment has demonstrated excellent performance for more than two years. The following describes and discusses its application in color digital proofing and its comparison with traditional printing proofing.

Unique color rendering system and rich color expression

The colorant (Donor) of ApprovaI XP includes four basic colors of CMYK. Also included are orange (0range), blue (Blue), green (Green) three spot colors, and silver (Silver) and white (White) two special colors. During the proofing process, one or several coloring materials interact on the intermediate medium to form a joint image, which is then applied to the substrate by a laminator to obtain the final proofs. Using these 9 color rendering materials, it is possible to reproduce the various colors of the original and some originals with special printing processes. The color of various color rendering materials is finally superimposed on the intermediate medium. The color rendering effect of various colors is controlled by the laser inside the machine. The size of the laser value determines the depth of the color, ranging from -99 to +99. We usually speak of a color of 0%-100%.

Approval XP's rich color performance not only satisfies ordinary offset printing, but also has strong color reproducibility for flexible printing, embossing, gravure printing, and screen printing commonly used in flexible packaging printing. For proofing on special materials, such as plastic film, transparent PET, stickers, iron sheet, etc., traditional printing and proofing cannot be performed, and Approval XP proofing system can solve this problem well. Due to the white color rendering material, when color proofing is performed on a transparent material, a white coloring material can be applied to the lowermost layer of other colors. In practical applications, if only one layer of white coloring material is printed, some colors will have large deviations. The effect is not ideal. Two layers should be printed at the bottom, and then other colors should be printed. Although the cost will increase, it will eventually increase. The resulting proofing effect is very satisfactory. The Generation and Use of Spot Colors in ApprovaI XP System

If we want to generate a new spot color, we can get the standard color card or obtain the L*, a*, b* value of the spot color from the customer first. When we obtain the ΔE value of the standard color card, we should first find the color standard that is close to the ΔE value of the required spot color from the existing standard color card library and read the color component (various color rendering materials). The composition of) the laser value. Then, in the Approval XP proofing system, a color card centered on the color and containing multiple colors is generated to measure each primary color, and the measured ΔE value is compared with the ΔE value of the standard color card. Find the color closest to the ΔE value of the standard color card. Finally, read out the various lasers to generate the color needed for the color, and enter it into the Recipe Builder box (as shown in Figure 1), so that a new spot color is generated. .

Approval XP's color rendering system consists of daily coloring matter. Generally speaking, it is sufficient to generate a spot color with two or three color rendering materials. The use of coloring materials should follow the principle of “never less, more”, first consider whether the two color materials can meet the requirements, if you can not get similar values, then consider adding a color material. This is not only to control the production cost, but mainly because the spot colors generated by the two coloring materials are more stable and are not easily exposed to external temperatures. Due to the influence of humidity, spot colors generated by the three coloring matters will undergo color difference due to the influence of external factors in the future use. The generated spot colors are compared with the standard color cards, and the △E value is less than 2.5, which is far higher than the national industry standard requirement for fine prints (ΔE is less than 4.0).

Flexible packaging products use a large number of spot colors, and the laser value required for the same spot color to appear on different types of substrates is different. The density value parameters for generating spot colors are different. This requires the generation, management, and use of spot colors. To have a complete system, otherwise it is easy to make mistakes when exporting proofs. When the same spot color is printed on different types of substrates, different spot color names need to be generated according to different laser values, and consistent naming rules should be maintained for the same type of substrates. In this way, the pre-press production will immediately be able to correctly name various types of spot colors in the document, depending on the type of substrate.

Metal color is widely used in packaging printing, especially flexible packaging printing. Approval XP's color rendering system provides a silver color rendering material more than the general color digital proofing equipment. This special colored coloring material can be used in conjunction with other coloring materials to produce a wide range of metallic effects. For example, to achieve a different color of gold, only Magenta and Yellow (Yellow) need to be adjusted. ) The density of the two coloring materials is sufficient.