Spot color and its characteristics

First, spot colors and their characteristics

Spot color ink is a kind of pre-mixed special color ink, such as fluorescent yellow, pearl blue, metallic gold silver ink, etc. It is not mixed out of four colors of CMYK, and color registration means accurate color. It has the following four characteristics:

1, accuracy.

Each color registration has its own fixed hue, so it can guarantee the accuracy of the color in printing, thus solving the problem of color transfer accuracy to a great extent;

2, on the ground.

Spot colors generally define colors in solid colors, regardless of how light they are. Of course, Tint can also be given to display any shade of spot color;

3, opacity.

Spot color ink is a covering ink, it is opaque and can be covered in the field;

4. Wide color gamut.

The color gamut in the stock color stock is very wide, exceeding the RGB performance gamut, not to mention the CMYK color space, so a large part of the colors are incapable of being represented by the CMYK four-color printing ink.

Second, the reason for choosing to use color in color dot printing

In color dot printing, the characteristics of spot inks are often used to select and use them. In general, it is generally used in two situations:

1. Print color visible light outside the color space of some CMYK four-color printing inks. The color gamut of CMYK four-color printing ink is obviously insufficient compared with the visible color gamut, while the color gamut of spot color ink is wider than that of CMYK four-color printing ink, so it can express many colors other than CMYK four-color ink;

2, to make up for the lack of printing technology. Due to the errors of various processes in the overall printing process, equipment maintenance, operating environment, artificial omissions and mechanical wear and other issues, it is difficult to obtain even and smooth dot colors when printed at 153 or less dots. At this time, we can use the same color. The full version of the color (ie spot color in the field) instead of a small dot for printing, it can be easier to get a flat large area color. In addition, sometimes in order to be able to clearly display fine graphics, such as fine strokes of mixed color graphics or invert white lines, etc., spot color processing is often used in order to achieve fine line drawing can be sufficiently realistic and delicate.

Third, pre-press use of spot colors should pay attention to some issues

1, the unity of spot color names.

In different software, the names may be different for the exact same two colors. For example, FreeHand named PANIonEI IF5 as PANTIONE 1F5CVC. In this way, when FreeHand graphic objects are placed in PageMaker, the same color will have three names. When the color separation is output, three printing plates will be generated, causing output errors. Therefore, if the data file needs to be used in more than two kinds of software, before the integrated color separation output, it must be noted that the use name of the same spot color must be unified. The more commonly used method is the color name in the tight distribution software, and the name of the same spot color is renamed as a unified name in the palette of various software.

2, spot color screen angle.

In general, spot colors are printed in the field, and they are rarely processed at the outlets. Therefore, the point of spot color screening is rarely mentioned. However, when using a lighter mesh color, there will be problems with the design and modification of the spot color screen dot. If the spot color of a dot has the overprint area following the colors printed by other dots, the spot color screening problem must be considered. At this time, if the angle formed by the spot color screen's screen angle and other color screen angles is less than 30 degrees, it will cause the screen to generate moiré; if the angles overlap each other, it will cause ink overprint problems, which will cause prints The color is seriously distorted. In addition, the screen angle of spot colors is generally preset to 45 degrees in software (45 degrees are considered to be the most comfortable angle for human eyes, so that the dots can be arranged in the same direction as the horizontal and vertical lines. The ability of the human eye to detect dots, if it is a bi-tonal image or data file, it is printed with four colors and black (usually 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,) there are spot colors, or there are more than two spot colors, then in the color separation screening will be output at 45 degrees, so when using shallow network for spot colors, if There may be overprinting with other screening colors. You must open the software color setting or print setting dialog box when the color separation is output to modify the spot color screening angle.