Epson Expression 636 User Manual - TWAIN 32 - Page 106

The resolution that you use to scan an image (input resolution) does not have to match the dots per inch of your printer (output resolution). Input and output resolution are two quite different measurements. Just follow the guidelines below. Optimum scanning resolutions Output device Line art Monochrome printer 300-600 Desktop or office color printer 300-720 Printing press or imagesetter 600-1200 Computer Screen 72 Grayscale 80-170 150-240 150-350 72 Color - 150-240 150-350 72 Here's how to calculate more precisely the required resolution for grayscale or color on an electronic color printer or a printing press: 1. Find out the lines per inch of the printing method. This is the measurement of resolution for high quality image printing. Do not confuse it with dots per inch, which is not an equivalent measurement. 2. Multiply the lines per inch by two to find the best scanning resolution. For example, for 175 lines per inch (a common resolution for magazines and books), scan your image at 350 dpi (2 × 175 = 350). For even smaller file sizes, try scanning at about 1.5 times the lines per inch. This may cause little or no perceptible loss of output quality. B-16 Expression 636 Scanner Settings