Knowledge of Colorful Printing Design

In printing design, the three primary colors of ink are mixed in different proportions to obtain the desired color spectrum hue values. The density of the three primary inks on the printing substrate in printing design and whether they are correct and balanced have a direct relationship with the design personnel. Although the printing design operators can only measure and set the ink density within a limited range, these density ranges can help the printing design personnel obtain a wide range of overprint ink colors, regardless of whether the ink is transparent or the substrate is pure white. In printing design, we can easily find these density ranges in various related publications: such as in the FIRST and SWOP standards.
In printing design, based on the ink density range specified in the instructions, any ink overlay sequence can be used, namely YMC, YCM, CMY, CYM, MCY, or MYC. But does each of these sequences produce the same color in printing design? Actually, no.
Even if the actual density is controlled within an absolute value, each overlapping sequence in the printing design will result in different overlapping colors of red, green, and blue, because the ink formulations used in each printing design have their own distinct properties, such as the ink opacity that affects the coverage rate. Therefore, the surface energy of the dried ink layer that is printed first will affect the adhesion characteristics of the wet ink that is printed later.
The covering power of the yellow pigment is poor, while that of the magenta and cyan pigments is good. However, the surface energy of the yellow ink is high.
The first step in color management in print design is to determine the optimal order of ink inking and the density balance that can provide a wide color gamut.
The GATF association developed a simple color hexagonal chart many years ago to visualize the ratios of different colors. The densitometer can display the quality of colors by measuring hue deviation, gray level, and overprint color, and compare them with the three primary colors.
For instance, in the hexagonal color chart, the three corners that are not adjacent to each other represent the three primary colors of the ideal ink (YMC), while the other three corners represent the overlay composite colors (RGB). The center of the hexagon represents the neutral color (from white to gray to black). The stronger the ink color intensity, the closer it is to each corner, and the farther it is from the neutral color.
When the printing colors and composite colors designed for actual printing are distributed in the hexagonal color chart, the densities, color differences and gray values of the primary color inks (CMY) and the composite colors (RGB) are revealed.
Because the ink is not ideal, the hexagonal (irregular) distribution will not be of the same size as the entire ideal hexagonal color map, but it can still be used for optimal printing. Therefore, using the GAFT method to achieve the irregular hexagonal distribution to display the color information of the three primary colors and composite colors in the printing design can result in the best density and overprint sequence.
By measuring the size of the color coverage area, the overall color performance of the ink and the contrast intensity of the printed design colors can be determined. Of course, the larger the area, the better.
Other density values can also be distributed as part of the measurement sequence for printing design, such as the 25%, 50.5%, and 75.5% dot density values of colors.
If the distribution of these other color values is concentrated, it indicates that the printing design is under control. Conversely, if the distribution is not concentrated, it means that the printing design has lost control and necessary adjustments should be made.