take out dots on scan of printed page

I must use a scan of an isometric drawing from a printed brochure. Any tips on how to minimize the printed dot pattern. I made the scan at 720 dpi figuring that a reduction would make the dots disappear. But that didn't work very well.

TIA

dp

In article <ab5ea$429f615b$4528bfab$>,
bogus wrote:

I must use a scan of an isometric drawing from a printed brochure. Any tips on how to minimize the printed dot pattern. I made the scan at 720 dpi figuring that a reduction would make the dots disappear. But that didn't work very well.

Best way is to use your scanner software. Most scanner software has an option for scanning printed material which will automatically remove the halftone pattern.

--
Art, photography, shareware, polyamory, literature, kink: all at http://www.xeromag.com/franklin.html

bogus wrote:

I must use a scan of an isometric drawing from a printed brochure. Any tips on how to minimize the printed dot pattern. I made the scan at 720 dpi figuring that a reduction would make the dots disappear. But that didn't work very well.

Doesn't your scanner software have a 'descreen' option? That's for removing those patterns. Otherwise scan at high resolution, use a little Gaussian Blur to remove the patterns and use Unsharp Mask afterwards to restore the detail as much as possible.

--
Johan W. Elzenga johan<<at>>johanfoto.nl Editor / Photographer http://www.johanfoto.nl/

"bogus" wrote in message

I must use a scan of an isometric drawing from a printed brochure. Any tips on how to minimize the printed dot pattern. I made the scan at 720 dpi figuring that a reduction would make the dots disappear. But that didn't work very well.

TIA

dp

There is a very effective technique of removing regular patterns like this using an FFT filter - to see a detailed description of how to, see this thread:
http://www.retouchpro.com/forums/showthread.php?t=10660& page=3&pp=15&highlight=fft Scroll down to the post by Cameraken titled 'summary'.

In article <429f883c$0$27873$
01.sydney.pipenetworks.com.au>,
says...

- snipe -

There is a very effective technique of removing regular patterns like this using an FFT filter - to see a detailed description of how to, see this thread:
http://www.retouchpro.com/forums/showthread.php?t=10660& page=3&pp=15&highlight=fft Scroll down to the post by Cameraken titled 'summary'.

Thanks! I thrashed around a lot a few years ago trying to develop the FFT and inverse FFT filters and never got them to work right. These do the trick beautifully!

Jason