Spot color ink printing considerations

Spot color ink printing considerations
Things to note when printing spot color inks:
The angle at which spot colors are screened
In general, spot colors are printed in the field, and dot processing is rarely done, so the angle of spot color ink screen is generally rarely mentioned. However, when using a light screen of color registration, there is a problem of designing and modifying the screen angle of spot color ink dots. Therefore, the screen angle of the spot color is generally preset to 45 degrees in the transfer (45 degrees is considered to be the most comfortable angle perceived by the human eye, and arranging the dots in the direction equal to the horizontal and vertical lines can reduce the human eye’s ability to perceive the dots).Paper box
The conversion of spot colors to printed four-color
Many designers often use the colors in some spot color libraries to define colors and color processing when doing graphic design, and convert them into CMYK printing four colors when separating.
There are three points to note:
First, the spot color gamut is larger than the printing four-color color gamut, in the conversion process, some spot colors can not be completely fidelity, but will lose some color information;
Second, it is necessary to select “spot color conversion to four colors” in the output selection, 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 us to reproduce the effect of the spot color with the same CMYK composition of the printed four-color ink (if you can, you don’t need spot color) In fact, if it is really concocted, the obtained color will have a big difference in hue.
Spot color trapping
Because the spot color is different from the printing four colors, (the printing four-color ink is overprinted with each other to generate an intercolor, that is, its ink is transparent), the use of the two spot colors usually does not produce an intercolor, intuitively speaking, that will get a very dirty color effect, so define the spot color, generally do not use the overprint method but use keepaway. This way, when using spot colors, as long as there are other colors next to the spot color graphic, you should consider appropriate trapping to prevent it，The cost of spot color printing，Dates box
Generally, spot color printing is usually used for printing below three colors, and if more than four colors are required, CMYK four-color printing is appropriate. Because CMYK four-color printing is basically presented in dot overprinting, and the use of spot colors is basically printed in the field, although usually spot colors are only used in the part of the image, in addition, if the same layout already has a four-color process color, for printing is equivalent to translating one more color, if printing and there is no extra printing unit (such as less than four-color printing press or four-color printing machine), it takes twice as long to print, and the cost is higher.