# My scanner has a resolution of 9600x1200 dpi -- what do those numbers mean? The number of elements in the CCD array (above) determines the x-direction resolution.

Scanners vary in resolution and sharpness. Most flatbed scanners have a true hardware resolution of at least 300x300 dots per inch (dpi). The scanner's dpi is determined by two factors:

• The x-direction sampling rate - This is determined by the number of sensors in the CCD imaging array.
• The y-direction sampling rate - This is determined by the precision of the stepper motor.

Let's take a simple example: If a scanner's resolution is 300x300 dpi, and that scanner is capable of scanning a letter-sized (8.5x11-inch) document, then the CCD has 2,550 sensors arranged in each horizontal row -- 8.5 (inches across) x 300 (x-direction sampling rate) = 2,550. A single-pass scanner would have three of these rows for a total of 7,650 sensors. The stepper motor in our example is able to move in increments equal to 1/300ths of an inch.