A scanned photo often begins its journey as a negative. The negative is then developed into a photo print. The photo print is then scanned. This journey often has a negative impact on the sharpness of the photo. The human eye perceives bright/dark edges, known as contrast edges (detail contrast), as sharpness. In SilverFast, it is possible to improve the sharpness of an image with the USM (Unsharp Masking) tool. The USM tool accentuates contrast edges without changing the colour saturation of the image itself. As a result, the image appears sharper thanks to a now richer detail contrast.

SilverFast’s Auto-Sharpness tool substantially simplifies the re-sharpening process. The Auto-Sharpness tool automatically sets an appropriate base-sharpness depending on the scanner’s resolution. With USM, professional sharpening is available with the click of a button. The resulting sharpness can then be adjusted according to the personal preference of the user. It is important that, when possible, the final adjustments take place in an image view of 100%. This is important because the effect of the USM tool is subject to the resolution of the image. A lack of sharpness is recognizable by washed out and blurry edges. Furthermore, image details, that lack a clear detail contrast to their respective environment, also tend to point to an unsharp image. Conversely, too much sharpness is noticeable with the appearance of doubled edges, which are often enveloped by a bright line.