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On Wed, 09 Aug 2006 00:11:57 +0400, shampayne
> The one major thing that I have been unable to find in Fireworks
> 8 is how to remove Moir? Patterns.
Well, from your post I decide that you are using Windows. Then, I may
suggest you some third-party freeware, that, although not being as much
user friendly as PSP and FW, often is much more efficient when it comes to
removing moire or halftone screen patterns. The software is called "Image
Analyzer" and is available for free here:
The key feature you need is called "Frequency domain filter".
Now a bit of theory on Fourier transform and frequency spectrum stuff
(just in case you weren't learning related math at University).
FT is about representing the image (or other data) as a composition of
sine functions (sine function is periodic or "harmonic" wave). From
ordinary average guy's point of view, describing the photo as huge set of
waves added together is senseless, but scientists think different.
Interesting thing happen, if our image *really* have some periodic
component in it. Regardless of what is this component - periodic texture
of the wall, or ladder, or just periodic pattern of printed halftone in
image, or result of interaction of periodic halftone with periodic nature
of scanning which we know as "moire" - it will give us high peak in
frequency spectrum (that is, in image representing how intensive are waves
of dirrerent frequencies). We can detect that peak and, if necessary, edit
or even remove it, thus editing or removing this particular signal from
Now we go to the practical part. You should scan your images at ppi at
least twice as high as printing halftone screen lpi. Most printings are
done with lpi about 150, and newspapers often at even lower values, so you
should scan them at 300 ppi at least (and without any software sharpening
scanner may offer you). Then open image with Image Analyzer. Then go to
Filter -> Frequency domain filter. Now you see the frequency spectrum of
the image. In the dialog, you may need to click "View scale" down scale a
couple of times so the image is easier to view. The image you see is
likely to look like the galaxy of white stars spreading from the top
center part to the edges. The top center part is brightest. Beside it, you
are likely to see some additional bright stars (high peaks) apart from it,
forming some sort of a pattern. These are the peaks representing our
"parasite" periodic pattern in the image. So you should just paint black
over them, checking out the intermediate result with "Preview" button.
Important point is: don't hit the bright spot at the top center area, this
is useful signal. Only hit the "lone stars" far from it. Once you're
satisfied, hit "Ok" and save the image.
Althought the technique may look complicated (again, only in case you
weren't learning related math at University), I often found it to be most
efficient when dealing with halftone or moire. I can make some suggestions
more related to "pure FW" way of doing job if you're interested, but I
personally highly recommend learning this trick.
http://photoshop.msk.ru - Photoshop plug-in filters