Remove Moire on Scans
Images in print media represent a series of overlapping dots
that should create an illusion of more colors. When you scan such a photo you can
usually discover a moire pattern. A moire pattern results from incorrect
screen angles of overprinting halftones.
You can try to avoid moire at the scanning stage. Sometimes
a well-chosen scan angle can produce a remarkable effect. However, if you deal
with a scanned image you have only one method of the moire suppression at your disposal - apply image
processing techniques.
On the photo below you can see a scan of a music CD cover.
Moire is visible.
Open this fragment of the scanned cover in a photo editor
and call the plug-in AKVIS Noise Buster.
Press the button Automatic Filtering to start
the automatic filtration: the program will analyse noise on the whole image and
offer its settings for the parameters Noise Level and Smooth
Level for every noise type.
By default the parameter Fade is set to
75%. It means that certain amount of original noise is mixed to the filtered
image. In most cases a bit of the original noise adds to the natural look of
an image. However, in this case, when the noise is not regularly spread over the
surface but represents visible squares, it's better to increase the value
of the parameter to 100%.
If the result in the preview area is good, press the button  to
apply the filtering to the whole image. Then apply the result to the picture in
the photo editor's workspace by pressing the button  .
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