Measurement that indicates how many pixels were digitized per unit of length and corresponds to the resolution of the image data. For multi-color offset printing with a resolution of 60 dots per centimeter (equivalent to 150 dots per inch), the output frequency should be in the range of 300 dots per inch so that four pixels (two in each direction) are provided for the rendition of the dot. In black and white images, the output frequencies are up to 2400 dots per inch, as all details must be produced. Depending on the necessary scale-ups and scale-downs of the original to be reproduced, the necessary resolutions in the scanner are substantially higher or lower.