PE2 - Moire pattern removal

[Richard Hirschman]

In Paint Shop Pro, there is a specific tool for moire pattern removal. I cannot find such a tool in Photoshop Elements 2. How can I remove the moire pattern from an image in PE2? (Sometimes the moire pattern remains, even after using the descreen setting while scanning an image.) Thanks.
Richard Hirschman

[BobHill]

Richard,

You can NEVER completely get rid of Moiré, as it's caused by a conflict in patterns between two devices creating the patterns on a different angle. But, you can sometimes diminish the Moiré effect first by scanning at a different angle to begin with, scan at a lower resolution (but still printable one) so as not to pick up so much of the original pattern. The original pattern usually comes from scanning a previously printed image (like from a book or magazine). And since a scanner creates a pattern also (sensors have a set pattern), that's the second device.

And then in Elements you can diminish the Moiré effect by adding a blur to the image. The more sharp the image, the more the pattern will become evident.

Bob

[John Gasal]

Richard,

Adding to Bob's response, I have been able to minimize or eliminate the Moire' effect by scanning at a higher resolution than I need, then resizing in Elements to a smaller resolution.

John

[Carl Wegner]

If this is about scanning of "magazine type dot printed" material, PSE's gaussian blur filter is more precisely controllable than most scanner software descreen settings. Either way you have to give up some sharpness to get rid of the dot aliasing effect.

Carl

[Chuck Snyder]

Carl, I haven't tried this, but after reducing the dot aliasing with
Gaussian Blur, you may be able to regain some of the sharpness using one of
the 'edge sharpening' routines described in various tutorials. Just a
thought....Chuck

[Wayne Fulton]

In article <1de97...@WebX.la2eafNXanI>, 71513...@compuserve.com says...

To do manual descreen, first scan at as high a resolution as is practical for
your computer/scanner situation. Even if you you only need a 75 dpi size scan,
scan at least at 300 dpi. 600 dpi or 1200 dpi would be even better
for a small page area (however a full page at 600 dpi color is 100 MB and may
not be possible for much low-end equipment).

Moire is caused by insufficient resolution to resolve the screen dots, so more
is better in this case. Moire is the absolute pits at 75 or 100 dpi, and
almost bearable at 300 dpi, and not much problem at higher resolutions.

Then simply resampling it smaller to be the desired image size is normally all
you need, followed by modest sharpening.

But if still any problem, like if you only scanned at 300 dpi, you could very
slightly blur it before resampling smaller, using ONE of the Elements Median,
Despeckle, or Gausian Blur filters before resampling. Median and Despeckle
normally work very well, Gausian works fine but is often a bit extreme. Only
use ONE of these. Doesnt take much. Blur first, then resample smaller, then
sharpen modestly. Judge results by viewing only at 100% Actual size on the
screen, else the video screen can give a false moire impression.

This should be a very complete and easy solution, and the best possible
solution.

--
Wayne
http://www.scantips.com "A few scanning tips"

[Richard Hirschman]

Hi,
Thanks to all who responded - very helpful.
Richard

[fool_in_school]

I have run into this problem lately. I have a bunch of scans that I am eventually wanting to edit into Avid HD, but wanted to do pushes on these old photos in After Effects. I have found that the slightest Gaussian Blur in Photoshop works a little. Interesting that someone said to scan at another angle. I'll have to give that a shot. Does anyone know if there are any other filters that could be applicable to reduce moire patterns even further once these steps have been taken?