How to control four-color offset printing (CMYK)

The core of CMYK control lies in precise registration and proper color registration. To prevent color misalignment, ghosting, or color overflow, the registration error must be strictly controlled between ≤ 0.1 mm (high precision) and 0.3 mm (standard). Below is a brief analysis covering prepress design, printing equipment, and the printing process; it can be said that prepress preparation plays a direct role in ensuring accurate color registration. 1. For lines and text: the finest lines should be at least thickened to 0.2 mm; small fonts should not be printed in four colors – they must be printed in monochrome. 2. At the boundaries of multi-color images: to prevent white areas from appearing, a blind registration process should be applied to the CMYK sections—for example, expanding the dark edges outward by 0.05–0.2 mm. 3. Keep the total CMYK ink volume within an appropriate range. Theoretically, each CMYK value can range from 100% to a maximum of 400%; however, the maximum allowable value varies depending on the printing method. For example, the upper limit for offset printing on coated paper is 300%, for color boxes on white cardstock it is 260%, and for watermarks on corrugated cardboard it is 200%.4. Ensure that the side and front guides on the paper feed table are stable; simultaneously, adjust the machine pressure according to the paper thickness to prevent paper stretching or deformation during the printing process, which could affect registration accuracy. 5. Place a cross-registration line on the plate; during printing, check whether this line is fully overlapped. 6. Of course, frequent stop-and-start operations during the printing process often lead to minor misalignments of the printed paper or plates, as well as inaccurate color registration.