Question: What if I use three colors for seven-color printing?
Answer: The use of enhanced gray component substitution (GCR) allows us to use only three different screening angles in a seven-color printing process to achieve good color printing without causing color changes. Let's assume that we have black as the main color, and its screening angle is 45°. The other six colors: cyan, blue, magenta, red, yellow, and green will alternate in turn with the angles of 165° and 105°. In this way, we can produce a variety of shades in three colors. They are the black that provides the gray component of the image and the two adjacent colors.
For example, we can use black and red and yellow to produce all printable colors between red and yellow. Without causing color differences, we can add up to 10% of complementary colors to deepen the color effect. Essentially, in one area of ​​an image, only three colors need to be printed.
