Computer Graphics with Photoshop - problem scanning newspaper or printed photographs

Author

problem scanning newspaper or printed photographs

Dugjak

2004-06-01, 7:14 am

I am new to Photoshop 8 CS. I am scanning photographs for a book that will
be offset printed, problem is that some of the original photographs are no
longer available and I have to work from either newspaper prints or prints
in existing books. When I do this I get a 'moire' effect and the printed
scans are unsatisfactory. My scanning software does not have a control to
remove this effect (at least I cannot find one). I have read that I should
use a blur effect. Is there a filter in photoshop designed for this or a
particular plug-in that will assist me?

Xalinai

2004-06-01, 12:14 pm

On Tue, 1 Jun 2004 19:58:05 +1000, "Dugjak" <dougmckean@iinet.net.au>
wrote:

>I am new to Photoshop 8 CS. I am scanning photographs for a book that will
>be offset printed, problem is that some of the original photographs are no
>longer available and I have to work from either newspaper prints or prints
>in existing books. When I do this I get a 'moire' effect and the printed
>scans are unsatisfactory. My scanning software does not have a control to
>remove this effect (at least I cannot find one). I have read that I should
>use a blur effect. Is there a filter in photoshop designed for this or a
>particular plug-in that will assist me?

Are you asking where to find the blur filter or whether there is a
de-moiré plugin?

Michael

Dugjak

2004-06-02, 12:14 pm

My scanning software has a descreen option. I now understand that if I scan
at a lower resolution (say 300 dpi instead of 600 dpi) I will get a better
result in this situation.

Is there a de-moire plugin for photoshop. If so, what is it called?

"Xalinai" <xalinai_Two@xalinai.de> wrote in message
news:40bc5da0.49397828@news.t-online.de...
> On Tue, 1 Jun 2004 19:58:05 +1000, "Dugjak" <dougmckean@iinet.net.au>
> wrote:
>
will[color=darkred]
no[color=darkred]
prints[color=darkred]
should[color=darkred]
>
> Are you asking where to find the blur filter or whether there is a
> de-moiré plugin?
>
> Michael

Odysseus

2004-06-02, 11:14 pm

In article <40bdbeea$0$8110$5a62ac22@freenews.iinet.net.au>,
"Dugjak" <dougmckean@iinet.net.au> wrote:

> My scanning software has a descreen option. I now understand that if I scan
> at a lower resolution (say 300 dpi instead of 600 dpi) I will get a better
> result in this situation.
>
> Is there a de-moire plugin for photoshop. If so, what is it called?
>
The two main ones are called "Blur" and "Rotate". ;)

Seriously, you can sometimes reduce moiré by scanning an image slightly
crooked and then straightening it out in Photoshop. Slight changes to
the scan resolution can also make a big difference; a moiré that appears
strong at 300 ppi might be much less apparent at 290 or 310 --
experiment! There's certainly no point to scanning a printed piece at a
resolution more than twice the original screen ruling: say about 150 ppi
for newspapers or 250-300 ppi for magazines; all you'll get is clearer
renditions of the halftone dots, which you *don't* want to see in the
final result.

--
Odysseus

Uni

2004-06-03, 4:14 am

Dugjak wrote:
> I am new to Photoshop 8 CS. I am scanning photographs for a book that will
> be offset printed, problem is that some of the original photographs are no
> longer available and I have to work from either newspaper prints or prints
> in existing books. When I do this I get a 'moire' effect and the printed
> scans are unsatisfactory. My scanning software does not have a control to
> remove this effect (at least I cannot find one). I have read that I should
> use a blur effect. Is there a filter in photoshop designed for this or a
> particular plug-in that will assist me?
>
>
>

If this moiré' pattern does not change when zooming in/out....

A.) Try rotating the image maybe 45 degree the scanner platen.
B.) Try various scanning resolutions. I prefer 400 DPI.

Uni

Aaron Queenan

2004-06-03, 12:14 pm

"Dugjak" <dougmckean@iinet.net.au> wrote in message
news:40bc532f$0$8095$5a62ac22@freenews.iinet.net.au...
> I am new to Photoshop 8 CS. I am scanning photographs for a book that will
> be offset printed, problem is that some of the original photographs are no
> longer available and I have to work from either newspaper prints or prints
> in existing books. When I do this I get a 'moire' effect and the printed
> scans are unsatisfactory. My scanning software does not have a control to
> remove this effect (at least I cannot find one). I have read that I should
> use a blur effect. Is there a filter in photoshop designed for this or a
> particular plug-in that will assist me?

Try using the median filter with a width set to roughly the distance between
adjacent blobs in the scan, then resize so that each blob becomes a pixel,
and finally unsharp mask.

Regards,
Aaron Queenan.

Kulvinder Singh Matharu

2004-06-03, 7:14 pm

On Tue, 1 Jun 2004 19:58:05 +1000, "Dugjak" <dougmckean@iinet.net.au>
wrote:

[snip]
>in existing books. When I do this I get a 'moire' effect and the printed
>scans are unsatisfactory. My scanning software does not have a control to

Nice tips here...

http://www.scantips.com/basics06.html

BTW, what scanning software are you using?

--
Kulvinder Singh Matharu
Contact details : http://www.metalvortex.com/form/form.htm
Website : http://www.metalvortex.com/

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