Suggestions For Removing Moiré Patterns - Xerox Nuvera User Manual

Problem Solving
Moiré patterns occur when scanning copying an original that is comprised of a halftone. Moiré is a form
of digital artifact that occurs when two regular patterns intersect to form a new pattern. Because the
new pattern is always more coarse that the two original patterns, the appearance will change as a
function of screen frequency and angle. Typically, the finer of the two originals patterns are the easier
it is to see the Moiré. Lower frequency halftone screens are less prone to visible Moiré.
Moiré can occur while viewing scanned halftones on a monitor screen, because the monitor has a certain
screen frequency, which may or may not be in alignment with the screen frequency and angle of the
original image.
Suggestions for removing moiré patterns:
• From Copy or Scan Services, select the Image quality tab.
• If your image contains a halftone, make sure you are NOT using Text Mode. If legibility of the the
text is important, and good reproduction of any pictures is also needed, consider using Mixed Text
& Halftones as the original type.
• Decrease the Sharpen control slightly. See
• Rotate the original slightly on the Document Glass.
• Scan/Copy at the highest possible resolution capable by the system.
• Wherever possible, scan/copy continuous tone images (for example, photographs) only. If there is
no continuous tone original available, scan/copy the halftoned image as a last resort.
• When submitting a print job, you may need to select a different halftone.
Tip
If you have programmed and run a job, and received unexpected results, ensure that the system-wide
settings are all set back to their defaults by clicking Clear All or Reset in the user interface. Then proceed
to do job programming pertinent to your job.
Examples
Figure 21: Result of two distinct patterns superimposed
Figure 22: Patterns with distinct screen angle and LPI frequency superimposed to form Moiré pattern.
18-6
Adjusting Sharpness (when scanning or copying).
Xerox ® Nuvera
User Guide and Training Aid (UGTA)
®