Canon CanoScan D646U User Manual page 58

Problem: No free disk space message displays when you start a scan
Solution: Since there is insufficient free space on your hard drive, clear non-
essential files to create more space.
Problem: Scanning is taking a long time
Solution: Resolution is set too high. Lower the resolution to the minimum
required settings and rescan.
Problem: Colors in the Preview area are strange
Solution 1: The original is faded. Try retouching the colors with an image editing
program. (image editing program manual)
Solution 2: Color balance and brightness are incorrectly set. Reset them.
Problem: Entire image is whited out (or blackened) when the image
type is set to black and white
Solution: The threshold value is set too low (or high). Increase (decrease) the
threshold value.
Problem: Scanning quality is poor
Solution 1: Resolution is too low. Raise it and rescan.
Solution 2: Original is floating off the document glass (platen). Place the original
correctly on the document glass.
Solution 3: Document glass or underside of the document cover is dirty. Clean
them.
Problem: Smudges are appearing on glossy color photo scans
Solution: Photos are adhering to the document glass are causing the light to
refract, creating the striped patterns. Shift the photo to a different
position on the document glass or clean the document glass before
rescanning.
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