14 Océ CS 5050/5070 User ManualScan resolutionChoosing the right resolution for the output print size (as well as the amountof scaling needed after scanning) determines the best scan resolution for eachimage. A resolution that is too low will diminish the print quality (insufficientdetail). A resolution that is too high slows down the raster image processor(OGSL) without adding quality to the image.Use the following guidelines to set end resolution:n 150 dpi for sharp, detailed images intended for close viewingn 100 dpi for viewing from a significant distancen Keep text and logos as vector information (i. e. Postscript fonts and formats),which will always print at the printer’s resolution.Most scanners can interpolate or “imitate” high-resolution scanning. However,do not use the interpolated resolution of your scanner to compute the imagesize. Instead, use the scanner’s highest true optical resolution to maintainimage quality.Post-scanning image correction and sharpeningBefore printing a scanned image, you must perform some basic imagecorrections and sharpening to ensure a high-quality, wide-format colour print.Tonal correction If necessary, remove the colour cast from the midtones of animage using a function such as “Auto" levels in PhotoShop. This functionallows you to re-adjust the black and white points in the image and redistributethe intermediate colours proportionately. In most cases, this correction issufficient for properly exposed images. However, in very dark night scenes orin very white snow backgrounds, you must make a manual correction byadjusting the histogram.Sharpening To improve the edge details of an image, use the “Unsharp Maskfilter” in Photoshop. This can digitally refocus an image that has becomeblurred from scanning or interpolation. A small over-estimation of the filtereffect can be diffused in the printing process; however, a large over-estimationcan give the image a hard, pixelated appearance.
