A moire pattern is a coarse, often cross-shaped pattern that can appear when scanning photographs printed in newspapers, magazines, or other halftone formats. This effect occurs due to the interference between the scanners sensor grid and the regular dot pattern of the printed image, creating distracting visual artifacts.
Many scanners include a descreening or moire reduction mode to help soften or eliminate these patterns, producing a cleaner and more accurate digital reproduction. Understanding moire patterns is important for photographers, designers, and archivists who work with printed materials to ensure high-quality scans.