Spot-color ink refers to a pre-mixed specific color ink, such as fluorescent yellow, Pearl blue, metal gold and silver ink, which is not a CMYK four-color mix, which means precise color.
Spot-color ink refers to a pre-mixed specific color ink, such as fluorescent yellow, Pearl blue, metal gold and silver ink, which is not a CMYK four-color mix, which means precise color. It has the following four characteristics:
Each color set has its own fixed hue, so it can ensure the accuracy of color in printing, thus dealing with the problem of color transmission accuracy to a large extent.
Spot colours are usually defined by solid colours, no matter how light they are. Of course, it can also screen the spot color (Tint) to show the arbitrary dark tone of the spot color.
Spot-color ink is a kind of cover-up ink, which is opaque and can stop the cover-up on the spot.
4. Wide gamut.
The color gamut in the register stock is very wide, beyond the performance gamut of RGB, let alone CMYK color space, so a large part of the color can not be rendered with CMYK four-color printing ink.
Some Problems Should Be Noticed in the Use of Spot Color before Printing
1. Unification of spot color designations.
在不同的App中，关于完整相同的两种套色，其称号可能会有所不同。如FreeHand把PANIONEI IF5 命名为PANTIONE 1F5CVC。这样一来，当把FreeHand图形对象置入PageMaker中排版时，同样的颜色就会有三种称号，分色输出时就会产生三块印版，形成输出错误。
In different software, there may be different titles for the same two sets of colors. For example, FreeHand named PANIONEI IF5 PANTIONE 1F5CVC. In this way, when FreeHand graphics objects are placed in PageMaker typesetting, there will be three designations for the same color, and three plates will be produced when the 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 need to unify the use of the same spot color title. The commonly used method is that the color titles in the tightening arrangement software are accurate, and the same spot color titles are renamed as unified titles in the palettes of various software.
2. The angle of spot color screening.
In general, spot color is printed in solid central mode, and seldom dot disposal, so the angle of spot color screening is seldom mentioned. But when using the light screen color of the set color, there will be problems in designing and modifying the angle of dot screening. If the spot color with dots follows the color of other dots and has overlay area, it is necessary to consider the angle of spot color screening.
At this time, if the angle between the dot screen angle and the other color screen angle is less than 30 degrees, it will appear to bump into the screen and produce tortoise lines; if the angle stacks with each other, it will cause the problem of ink overlay, which will form a serious distortion of the color of printed matter.
In addition, the dot screening angle is usually set to 45 degrees in software (45 degrees are considered to be the most comfortable angle for the human eye to perceive, so that the dots are arranged in the same direction as the degree and vertical line can reduce the human eye's ability to detect dots). If there is printing in a two-color image or data file. Four-color screen printing (usually in four-color screen printing, the black dots are 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, in the color separation screen will be 45 degrees output, so in the use of light screen for spot color, if it is possible to overlap with other screen colors. The dialog box of software color setting or printing setting must be opened when the color separation output, and the correction of spot color screening angle must be stopped.