In a printing workshop,"oil spots"(or"fish-eyes"—small, circular, unprinted white spots) are among the most difficult defects to troubleshoot. A sample might look perfect during a drawdown, only for white spots to appear once the job hits the press. A specific batch of film might run without issues, while another batch causes problems; or, the same ink might perform well on one job but result in surface defects on another. In Dongguan and the broader Guangdong region—a hub for gravure, flexographic, and screen-printing ink manufacturers—such issues are a recurring challenge. Experience shows that selecting the right anti-oil additive requires careful consideration of three key variables: the substrate, the printing process, and any downstream (post-printing) operations. Furthermore, the ink system—whether water-based, solvent-based, polyurethane (PU), or UV-curable—must be matched with the appropriate additive chemistry (e.g., polyether-modified silicones versus non-silicone alternatives). Only when these factors are correctly aligned can such defects be effectively suppressed. This article examines these phenomena as they occur on the press, offering a step-by-step guide on how to resolve oil spots and select the appropriate additive. The content does not target any specific company; it is intended solely as a technical reference based on ink formulation principles and printing practices.