Conversion from the most popular spot color to pri

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Conversion from spot color to printing four colors

1 Unification of spot color names. In different software, the names of two identical chromatic schemes may be different. For example, freehand named panionei 1f5 Pantone 1f5cvc or panione 1f5cvv, while PageMaker named it Pantone 1f5cv. In this way, when freehand graphic objects are placed in PageMaker for typesetting, the same color will have three names, and three printing plates will be generated during color separation output, resulting in output errors. Therefore, if the data file needs to be used in more than two kinds of software, before the integrated color separation output, we must pay attention to: the use name of the same spot color must be unified. The more commonly used method is to take the color name in the hair arranging software as the standard, and rename the name of the same spot color in the color matching of various software, which will also give the extruder industry endless development power board to a unified name

2. Spot color plus angle. Generally, spot colors are printed in a field manner, and little processing is done, so the angle of spot color addition is rarely mentioned. However, when using the light color of chromatic registration, there will be the problem of designing and modifying the spot color point with an angle. If there is a overprint area between a spot color and the color printed by other spots, the angle of spot color addition must be considered. At this time, if the angle between the spot color point and other colors is less than 30 degrees, there will be collision or moire; If the angles overlap each other, it will lead to ink overprint problems, which will cause serious distortion of the color of the printed matter. In addition, the addition angle of spot color is generally preset as 45 degrees in the software (45 degrees are considered to be the most comfortable angle for human eyes to perceive, and arranging the points in the direction equal to the horizontal and vertical lines can reduce the ability of human eyes to detect the points), If a two-tone image or data file has both printing four-color black (generally, in four-color plus printing, the black dot is placed at 45 degrees, yellow is 0 degrees, magenta is 15 degrees, and green is 75 degrees), and there are spot colors, or there are more than two spot colors, they will be output at 45 degrees during color separation plus. Therefore, when using light spot colors, if it is possible to overprint with other added colors, The dialog box of software color setting or print setting must be opened during color separation output to modify the spot color plus angle

3. The conversion from spot color to printing four colors. Many designers often use some colors in the spot color library to define colors and carry out coloring treatment when doing graphic design, and convert them into CMYK printing four colors when separating colors. At this time, we should pay attention to three points: and successfully put into mass production. First, the spot color gamut is larger than the printing four-color gamut. During the conversion process, some spot colors cannot be completely fidelity, and some color information will be lost; Second, the spot color must be converted into four-color selection in the output selection, otherwise it will lead to output errors; Third, don't think that the CMYK color value ratio displayed next to the spot color number can enable you to reproduce the effect of the spot color with four-color printing inks with the same CMYK composition (if you can, you don't need the spot color). In fact, if you do the same, the colors you get will have a big difference in hue

4. Trapping of spot color. Because spot colors are different from four printing colors (printing four-color inks generate intermediate colors by overprinting each other, that is, their inks have transparency), they usually do not generate one intermediate color by overprinting two spot colors, Intuitively, it will get a very dirty color effect (of course, there are exceptions, such as the intentional use of spot color overprint in the design to produce the required third color, which is produced by superposition and mixing. This third color is full, thick and solid, such as: spot color yellow embossed with modulated spot color red, two colors overprint to produce a stable dark red, which is often used as the cover of books, etc.), so the definition of spot color, Generally, overprint is not used, but keepaway is used. In this way, when using spot color, as long as there are other colors next to the spot color pattern, we should consider making trapping treatment suitable for making stronger and lighter plastic by adding graphene, so as to prevent the occurrence of white edge exposure (the method of spot color trapping and its related technical problems are complex, so we won't go into details here)

5. Spot color color matching system. When choosing a computer color matching system, first of all, you should know which is the spot color system and which is the CMYK four-color printing system, so as to know whether there will be color conversion and color distortion in the color output of the system you choose. For example, the commonly used color matching systems in graphic software include Pantone, trumatch, focoltone, Toyo ColorFinder, anpa-co. our company has after-sales points lor, ric color guide, etc. all over the country, among which trumatch, focol tone and ANPA colorr are systems developed on the basis of printing four colors, while others belong to spot color systems (Pantone system covers a wide range, including printing color and spot color). That is to say, in Pantone spot color, Toyo color finder, ric color guide and other spot color color matching systems, many colors have exceeded the printing four-color gamut and cannot be reproduced with four-color ink. The CMYK combination value provided by the system is only an approximate value

so if you choose the spot color to match the color in the system, and print four-color color separation output; Or refer to the corresponding CMYK combination values approximately displayed by the spot color in the system, and use these values to replace the original spot color with printed four colors, which will definitely lead to color distortion; Secondly, it should be understood that when the spot color matching system performs color separation, unless it is specially set to convert the spot color into CMYK four colors for output, each spot color used will be automatically divided into a color plate independently. In the same way, after the color in the printing four-color color matching system is used for coloring, the color will be automatically allocated to four printing plates according to the CMYK ratio value of the color itself during color separation output, without producing more color plates. Moreover, it should be noted that in the point front image environment, the selected color (such as spot color) will be automatically converted to the same color mode (such as CMYK four-color mode) as the data file to which the color is applied after being used on the canvas. Therefore, in dot matrix drawing software, spot colors must be deliberately added or specified (for example, adding and defining spot colors in Photoshop can be in two cases: if the spot color is applied to the whole image as a tone, the image needs to be converted into a two-tone mode, and the spot color is applied on one of the two-tone printing plates; if the spot color is used in a specific area of the image, the spot color channel must be created); In the vector drawing environment, if a spot color is selected or defined, the color will always exist as the attribute of the spot color, unless the attribute of the spot color is specially changed or converted into a printing color (for example, a spot color added and defined in IIIustrator, even if it is referenced to other illustrator data files or the data files using the spot color are opened with other vector software, the color attribute of the spot color will not change)

6. Cost of spot color printing. General spot color printing is usually used for printing below three colors. If more than four colors are required, CMYK four-color printing is appropriate. Because CMYK four-color printing is basically based on dot overprint, while the use of spot color is basically based on field printing. Although spot color is usually only used locally in the image, it is customary to estimate at twice the price of general printing ink when evaluating; In addition, if there are already four printing colors on the same page, it is equivalent to one more color for printing. If the printing machine has no redundant printing unit (such as less than four-color printing machine or four-color printing machine), it will take twice as long to print, and the cost will be higher

in short, special care should be taken when using spot color, otherwise it will not only cause color distortion, spoil your creativity and design, but also increase economic expenditure and unnecessary waste of time

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