Many users always scan using the highest resolution, the scanner will allow. This way, they hope to get the best scans possible. But this is often not the case. Interpolation does not obtain any additional image information, as the magnification is based solely on a mathematical computation of existing image data and creates pixels where there were none before. The physical resolution, which manufacturers often print on the box very prominently, is theoretically achievable but again, only through interpolation. In practice, the resolution which is actually usable for the scan, called optical resolution, does not reach this theoretic value. There are a number of reasons, e.g. the complex optics (mirrors and lenses) are limited and may cause unsharpness at the edges of the scan area.

The slider control indicates the true resolution with which the scanner is actually scanning. It should be used as an indicator rather than as a controller. The slider's color indicates if the chosen resolution is appropriate. In the red area, the resolution is interpolated, the scanner is not able to reach this resolution physically. The scanner easily achieves resolutions marked green, physically as well as optically. In between, from yellow toward red, although the scanner is physically designed for these resolutions, it does not always achieve them optically.

Use our Resolution-Target USAF 1951 to easily determine the highest resolution your scanner is actually able to achieve.