Magnetic Closure Box Of House Style prepress use spot color should pay attention to some problems

Magnetic Closure Box Of House Style prepress use spot color should pay attention to some problems

1. Unity of spot color names. In different software, the names may be different for two colors that are exactly the same. For example, PANIONEI 1F5 is named PANTONE 1F5CVC or PANIONE 1F5CVV in FreeHand, and PANTONE 1F5CV in PageMaker. This way, when you put a FreeHand graphic object into PageMaker, you will have three names for the same color, and when you print it out, you will have three plates, resulting in an output error. Therefore, if the data file needs to be used in more than two kinds of software, before the integrated color separation output, it is important to note that 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 arrangement software as the standard, and rename the name of the same spot color into a unified name in the color palette of all kinds of software.

2. Spot color mesh Angle. Under normal circumstances, spot color is printed in the field, and little dot processing is done, so the Angle of spot color mesh is rarely mentioned. However, when using the light mesh color, there will be a problem of the design and modification of spot color dot mesh Angle. If there is an overprint area between spot color and other spot color printing, it is necessary to consider the Angle of spot color mesh. At this time, if the spot color dot mesh Angle and other color mesh Angle formed by the included Angle is less than 30 degrees, there will be a collision or moire; If the Angle overlaps each other, it will lead to ink overprinting problems, which will cause serious distortion of printed color. In addition, the grid Angle of spot color is generally preset to 45 degrees in the software (45 degrees is considered to be the most comfortable Angle for human perception, so that the dot arranged in the direction of equal Angle with horizontal and vertical lines can reduce human perception of dot), if a two-tone image or data file has four-color black printing (generally in four-color screen printing, The black dot is placed at 45 degrees, yellow is 0 degrees, magenta is 15 degrees, green is 75 degrees), and there are spot colors, or there are two or more spot colors, when the separation and screening will be output at 45 degrees, so in the use of light grid color, if there is a possibility of overprinting with other screen colors, you must open the software color setting or printing setting dialog box when the separation output. The spot color mesh Angle is modified.

3. Spot color conversion to printing four colors. Many designers often use some colors in the color library to define colors and color processing when doing graphic design, and then convert them into CMYK printing four colors when separating colors. At this time, it is necessary to pay attention to three points: first, the spot color field is larger than the printed four-color field. In the conversion process, some spot colors cannot achieve fidelity, and some color information will be lost. Second, must be in the output of the choice of "spot color conversion into four colors" choice, otherwise it will lead to output errors; Third, do not think that the CMYK color value ratio displayed next to the spot color number can allow you to reproduce the effect of the spot color with the same CMYK composition printing ink (if you can do without spot color), in fact, if it is true, the color will have a big difference in hue.

4. Spot color trapping processing. Because spot color is different from printing four-color ink (printing four-color ink relies on overprinting each other to produce intermediate color, that is, its ink has transparency), it is usually not used to produce a intermediate color by overprinting two spot colors, which intuitively will get very dirty color effect (of course, there are exceptions, such as the intentional use of spot color overprinting in the design to produce the required third color, superimposed mixing. This third color is full, thick and solid, such as spot color yellow on the imprinting modulated spot color red, two colors after overprinting produce a stable deep red, commonly used for book cover, so the definition of spot color, generally do not use Overprint but Keepaway. In this way, when using spot color, as long as there are other colors next to spot color graphics, we should consider making appropriate trapping processing, in order to prevent the occurrence of white edge problems (about the method of spot color trapping and its related technical issues are more complex, this will not be described).

5. Color matching system for spot colors. When choosing the computer color matching system, first of all, it should be clear which is the spot color system, which is the CMYK four-color printing system, so as to know whether there will be color conversion and whether there will be color distortion in the color separation output of the system you choose. For example: Color matching systems commonly used in graphics software include PANTONE, TRUMATCH, FOCOLTONE, TOYO ColorFinder, ANPA-COLOR, RIC Color Guide, etc. TRUMATCH, FOCOL TONE, and ANPA COLORR are based on the four-color printing system, while others are spot color systems (PANTONE covers both spot and print colors). That is to say, in spot Color matching systems such as PANTONE spot Color, TOYO Color Finder and RIC Color Guide, many colors are out of the four-color range of printing and cannot be reproduced with four-color ink, and the CMYK combination value provided by the system is only an approximation.

So if you choose the spot color color matching system in the color, and print four color separation output; Or refer to the corresponding CMYK combination values of spot colors approximately displayed in the system, and use these values to replace the original spot colors with four printed colors, which will definitely lead to color distortion; Secondly, it should be understood that when the spot color matching system does color separation processing, unless it is specially set to convert the spot color into CMYK four colors for output, each used spot color will automatically be independently divided into a color plate. Similarly, after the colors in the printing four-color color matching system are used for coloring processing, they will be automatically assigned to four printing plates according to the CMYK ratio value of the color itself in color separation output, instead of generating more color plates. Also, note that in a lattice diagram environment, the selected color (e.g., spot color) is automatically converted to the same color mode (e.g., CMYK four-color mode) as the data file in which the color is applied when applied to the canvas. Therefore, in lattice drawing software, spot colors must be deliberately added or specified (for example, in Photoshop, spot colors can be added and defined in two cases: If a spot color is applied to the entire image as a hue, the image needs to be converted to a two-tone mode and the spot color is applied to one of the two-tone plates; If a spot color is used for a specific area of the image, a spot color channel must be created); In a vector drawing environment, if a spot color is selected or defined, the color will remain as a spot color unless the spot color is specifically changed or converted to a printed color (e.g. A spot color added and defined in Iiiustrator does not change its color properties even if it is referenced to another Illustrator data file, or if a data file using the spot color is opened with other vector software, etc.

6. Cost of spot color printing. General spot color printing is usually used for printing below three colors. If more than four colors are needed, CMYK four-color printing is appropriate. Because CMYK four-color printing is basically based on dot overprint color, and the use of spot color is basically printed in the field, although usually spot color is only used in the local image, but when the evaluation, it is customary to estimate the price of the general printing ink twice; In addition, if there are already four printing colors on the same page, it is equivalent to one more color for printing. If the press has no extra printing units (such as a press with less than four colors or a four-color press), it will take twice as long to print and the cost will be higher.

In short, the use of spot color should be particularly careful, otherwise it will not only cause color distortion, spoil your creativity and design, but also increase the economic expenditure and unnecessary waste of time.