Moire pattern in printing is a visual effect produced between two or more overlapping grids or periodic structures. This effect is due to interference between two or more periodic structures, causing changes in the visual effects observed by the human eye.
In printing, when factors such as improper arrangement of the dot angles for each color plate cause intermittent dots to form linear gratings that interfere with each other, patterns that should not appear in the printed image, namely moiré, will appear. Although moiré may be seen as a problem during the printing process, when cleverly designed and utilized, it can also play a unique role as an anti-counterfeiting technology in preventing counterfeiting.