I found a cool texture that I wanted to use in a National Geographic magazine. The problem is that once I scanned I get the crosshatched, moire artifacts. I know there is several ways to get rid of this in Photoshop, I scanned at 300 dpi and downsampled to 150 dpi and it helped, I also tried to use the median filter but it was a bit to much, even with the unsharp filter afterwards. Any suggestions???

Can you scan higher then 300? Here are some URL's that have some info: http://www.pixelfoundry.com/Tips/KPT10/KPT10.html http://www.pixelfoundry.com/Tips/KPT4/KPT4.html http://www.ruku.com/covergirlintro.html http://photoshoptips.i-us.com/photoshop4.htm I got these from: http://www.ex.ac.uk/~jastaple/photoshop/searchframe.html

I can take a picture with my digital camera for you and send it to you if you want. The resolution is GREAT! Just tell me which National Geographic magazine and what page and I will take a picture of it. afanton@mindspring.com -Adam

Thanks for all the links Traveler! Adam gave me an idea what if I take a picture of the texture and the scan the photo in the computer. Would it be to many generations? Yes I think I can scan at higher dpi. Why?

Well if you scan at a higher DPI you could do 2 or 3 reductions in size/DPI.

Best way I've discovered to kill the moire pattern is to scan it at the max resolution your scanner can do in hardware, or (say) 600dpi if you can do more. Then use the Gaussian blur filter to blend the haltone dots togeather, something around 2.2 or so pixels should be right, you want the point where the dots disapear, but you don't loose a lot of detail. Then resize it to about 1/2 or 1/4 that size. The whole idea is to blend the halftone pattern back into pixels.

I got this tip also: Convert your file from RGB to LAB. Apply Median filter on the Lightness channel, a channel and b channel separetely. Run Unsharp filter on Lightness channel only. Convert to RGB. I combined this with a 600dpi scan sample down to 133 dpiand it really got rid of the Moire.

Check to see if your scanner has a "descreening feature" If it does, use the setting for magazine print (usually 133 lpi). I work for a newspaper and we get all kinds of crap sent to us to scan, from yellow page ads to posters. It's a full time job just cleaning up bad scans. What issue/page # of NG? I may be able to scan it here on our equipment. For educational purposes, of course.

I just went and looked at the line screen in my NG mag. It looks like they're printing at something like 300 lpi. That's way higher than your average mag. Try scanning at a LOWER dpi. Also, try turning the mag to a different angle. If your scanner scans CMYK, don't use that setting. Scan in RGB. Give me a few hours and I'll come up with some more ideas.

I just went and looked at the line screen in my NG mag. It looks like they're printing at something like 300 lpi. That's way higher than your average mag. Try scanning at a LOWER dpi. Also, try turning the mag to a different angle. If your scanner scans CMYK, don't use that setting. Scan in RGB. Give me a few hours and I'll come up with some more ideas.

Sorry about the duplicate post. Gotta restrain that double-clicking index finger. I checked the screen on National Geographic. They print right around 200 linescreen. I was able to scan at 100 and 150 without getting any moire. I'll try to post a test today to show what settings I used.

I'd say try noise/despecle. Makes the imahe a tad soft, but works for me sometimes

Not sure what scanner you use, but my scanner, and a few others have options in the scanning software for when you are scanning from a magazine that do a fairly good job of removing the moire patterns, even at higher resolutions.

Mine is a Scanjet 4p without moire removal.Next time I will get one with deescreening feature.

The scanner I have seems to be the best one for those of us (including myself) who suffer from intermittent cranial vacuum disorder. It's an Agfa Snapscan 1212u. Pretty decent resolution, very easy to use and functional software. Outputs to photoshop well and stuff.

While on the subject how do you know the actual hardware resolution of your scanner? I have search in the documentation and found nothing.

In the documentation for my scanner it says both the hardware and software resolutions for it. 9600dpi software 1200x600 hardware. If it gives you two sets of numbers the lower set is usually hardware.

I have heard that scanning at an angle introduces more problems than solutions, sometiems it helps but most of the time it creates new ones, I wonder how does the deescrening feature works in a scanner. I have heard many suggestions for filters but it usually refer to median filter, despeckle filter and lastly a very low setting on the gaussian blur.