What is a CCD, and how does it affect a scanners performance?
CCD (Charge-coupled device) is the component that actually does the scanning. CCDs consist of an array of sensors that produce a signal when light hits them. The sensors are arranged in a “head” that moves back and forth across the image. The number of elements the head has across its length per inch is known as the hardware resolution of the scanner, which is usually 300 or 600dpi. When a scanner’s resolution is listed as something ike 600x1200dpi, the low number is the one that really matters. The 1200dpi figure means the scanner head stops at 1200 discrete positions everyinch while moving down the length of the image to produce the scan. The real resolution of the scanner is the software resolution (the lower number), because that tells you how many dpi the software reads.
