Some problems that should be paid attention to when using spot colors before printing
We are a big printing company in Shenzhen China . We offer all book publications, hardcover book printing, papercover book printing, hardcover notebook, sprial book printing, saddle stiching book printing, booklet printing,packaging box, calendars, all kinds of PVC, product brochures, notes, Children's book, stickers, all kinds of special paper color printing products, game cardand so on.
For more information please visit
http://www.joyful-printing.com. ENG only
http://www.joyful-printing.net
http://www.joyful-printing.org
email: 860681365@qq.com
1. The uniformity of spot color names. In different software, the names may vary for the exact same two sets of colors. For example, FreeHand named PANIONEI 1F5 as PANTONE 1F5CVC or PANIONE 1F5CVV, while PageMaker named PANTONE 1F5CV. In this way, when the FreeHand graphic object is placed in PageMaker, the same color will have three names, and three color plates will be produced when the color separation is output, resulting in an output error. Therefore, if the data file needs to be used in more than two kinds of software, be sure to pay attention to the use of the same spot color before the integrated color separation output. The more common method is to change the name of the same spot color to a uniform name in the palette of various softwares based on the color name in the software.
2. The angle of spot color screening. In general, spot colors are printed in the field, and dot processing is rarely done, so the angle of spot color screening is rarely mentioned. However, when using a light colored mesh color, there will be problems in designing and modifying the screening angle of the spot color dot. If there is a spot color in the spot color of the dot and other colors printed on the dot, you must consider the angle of the spot color. At this time, if the angle of the screen of the spot color dot is less than 30 degrees with the angle of the other color, the net will hit the net or generate a moiré; if the angles overlap each other, the ink overprint problem will occur, which will cause Serious distortion of the color of the print. In addition, the screen angle of the spot color is generally preset to 45 degrees in the software (45 degrees are considered to be the most comfortable angle perceived by the human eye, so that the dots are arranged in an angle equal to the horizontal and vertical lines to reduce The ability of the human eye to detect the dot), if it is a two-tone image or a data file, there are four colors of black printing (generally in four-color screen printing, the black dot is placed at 45 degrees, the yellow is at 0 degrees, If the magenta is 15 degrees and the blue is 75 degrees), there is a spot color, or there are more than two spot colors, then it will be output at 45 degrees when the color separation is applied, so if you use the shallow mesh for the spot color, If it is possible to overprint with other screened colors, you must open the software color setting or print setting dialog box during the color separation output to modify the spot color screening angle.
3. Conversion of spot colors to four colors of printing. Many designers often use the colors in the spot color library to define colors and coloring when they are doing graphic design, and convert them into CMYK printing four colors when color separation. At this time, you need to pay attention to three points: First, the color gamut of the spot color is larger than the color gamut of the printing. In the conversion process, some spot colors cannot be reproduced, but some color information will be lost. Second, the output must be selected. The spot color is converted into a four-color "selection, otherwise it will cause an output error. Third, do not think that the CMYK color value ratio displayed next to the spot color number allows you to reproduce the spot color effect with the same CMYK component of the four-color ink. If you can't use the spot color, in fact, if you do the same, the color will have a big gap in the hue.
4. Spot color processing of spot colors. Since the spot color is different from the printing four colors (printing four-color inks to create a color by mutual overprinting, that is, the ink has transparency), it is usually not used to create a color between two spot colors, which is intuitive to say that Get very dirty color effects (of course there are exceptions, such as the intention to use the spot color overprinting process in the design to produce the required, superimposed mixing of the third color, this third color is full, thick and real, such as: spot color yellow The embossed modulated spot color red, the two colors are overprinted to produce a stable dark red, often used as the cover of the book, etc.), so the definition of the spot color, generally does not use the overprint (overprint) method instead of empty ( Keepaway). In this way, when using spot colors, as long as there are other colors next to the spot color graphics, you should consider making appropriate trapping processing to prevent the occurrence of white-edge problems (the method of spot color trapping and related technical problems are more complicated, This is not to repeat).
5. Spot color matching system. When choosing a computer color matching system, first of all, it should be clear which color system is the CMYK four-color printing system, so as to know whether the color in the system you selected will have color conversion and whether it will be in the color separation output. A situation with color distortion occurs. For example, the color matching systems commonly used in graphics software are PANTONE, TRUMATCH, FOCOLTONE, TOYO ColorFinder, ANPA-COLOR, RIC Color Guide, etc., among which TRUMATCH, FOCOL TONE and ANPA COLORR are developed based on printing four colors, others All of them belong to the system of spot colors (the PANTONE system covers a wide range of colors, both print and spot colors). That is to say, in the spot color matching system such as PANTONE spot color, TOYO Color Finder and RIC Color Guide, many of them have exceeded the printing four-color color gamut and cannot be reproduced with four-color ink. The CMYK combination provided by the system. The values are also approximate.
So if you choose the color in the spot color matching system and output it in four color separations; or refer to the corresponding CMYK combination values that are similarly displayed in the system, and use these values to replace the four colors with printing. The original spot color, the result will definitely lead to color distortion; Secondly, it should be understood that the spot color matching system is used for color separation processing, unless the special color is converted to CMYK four colors to output, otherwise, each used Spot colors will automatically be independently divided into a color version. By the same token, after the color in the four-color color matching system is used for the coloring process, the CMYK ratio of the color itself will be automatically applied to the four plates when the color separation output is performed, without generating more. Color version. Furthermore, it should be noted that in the dot matrix environment, the selected color (such as a spot color) is automatically converted to the same color mode as the data file to which the color is applied (such as CMYK four-color mode) after being used on the canvas. . Therefore, in dot matrix drawing software, for spot colors, it must be deliberately added or specified (for example, adding and defining spot colors in Photoshop, there are two situations: if a spot color is applied as a hue to the entire image To convert the image to a two-tone mode and apply a spot color on one of the two-tone plates; if the spot color is used for a specific area of the image, you must create a spot color channel; in a vector drawing environment, When you select or define a spot color, the color will always exist as a spot color attribute unless you specifically change or convert the spot color attribute to a process color (for example, a spot color added and defined in Iiiustrator, even if it is referenced Other Illustrator data files or data files that will use the spot color are opened by other vector software, etc., and the color properties of this spot color are not changed).
6. The cost of spot color printing. Generally, spot color printing is usually used for printing below three colors. If four or more colors are required for printing, CMYK four-color printing is preferred. Because CMYK four-color printing is basically overprinting with dots, and using spot colors is basically printing in the field. Although the spot color is usually used only in the image, it is customary to pay twice the price of the general ink. To estimate; in addition, if there are already four printing colors in the same layout, it will be equal to one color for printing, if the printing machine does not have excess printing units (such as less than four-color printing presses or four-color printing presses) ), it takes another time to print, and the cost is even higher.
In short, use special colors should be especially careful, otherwise it will not only cause color distortion, ruin your creativity and design, but also increase economic expenses and unnecessary time waste.