A prescan is a quick, low-resolution scan of an image performed before a full, high-resolution scan. It provides a preview of the image on a monitor, allowing photographers or technicians to check composition, exposure, focus, and framing before committing to a detailed scan.
Prescanning is widely used in film scanning, flatbed scanning, and digital imaging workflows to save time and ensure accuracy. By evaluating the image at low resolution first, adjustments can be made to cropping, colour correction, and scanning parameters, ensuring optimal quality in the final high-resolution scan.