Halftone Patterns

Printed images are constructed out of patterns of halftone dots known as screens. If you scan a printed image, you will likely see this pattern of screened dots reproduced in your scanned image. If you then reprint this scanned image with the included halftone dot screen pattern, you will often produce a very visible and distracting reprint pattern known as moiré. This moiré pattern can be more obvious than the original pattern because of the complex interaction of the original printed screen with the new one. Removing the scanned halftone dot pattern is known as descreening. Like removing image capture noise and JPEG compression patterns, descreening images can improve the quality of your final printed image.