If the original is a printed document, moiré patterns (web-like shadows) may appear in the scanned image.
Check that Descreening is selected.
Click Settings in Epson ScanSmart, Review Scans or on the Select Action window, and then click the Scanner Settings tab > Scan Settings button > Advanced Settings tab on the Epson Scan 2 window > Descreening.
Change the resolution, and then scan again.
Click Settings in Epson ScanSmart, Review Scans or on the Select Action window, and then click the Scanner Settings tab > Scan Settings button > Main Settings tab on the Epson Scan 2 window > Resolution.