Scanning and Resolution Tips

Simple guidelines that work most of the time

These aren't hard-and-fast rules or formulas but they are tried-and-true guidelines that hold true most of the time.

Resolution

More is not necessarily better. Scan at no more than the output resolution or resample down to the resolution of the output device. If you are printing to a 300 dpi laser printer, scanning at 1200 dpi (ppi, see note below) results in a larger file with unneeded information that will be discarded by the printer.

DPI and LPI

The SPI should be double the LPI at which the image will be printed. Newspapers typically use 85 LPI so 170 SPI images are fine. Images in a typical magazine can be 266 SPI (133 x 2).

NOTE: DPI (dots per inch) properly refers to the printed output resolution of a device such as an imagesetter, laser printer, although in practice DPI is frequently substituted where the tersm SPI or PPI should be used. For a more detailed look at resolution see: Measuring Resolution Inch by Inch