scanned pictures

berenberen wrote on 12/23/2003, 7:08 AM

I'm working on a slideshow wth zooming and panning on stills.
I've scanned the stills at 300 dpi; they are bitmap files. Some of them - particularly those scanned from magazines - have this sort of pattern overlaying them that shows up only when opening them in Vegas, but not when viewing them in a photo viewer. This happens both with b/w and color, but looks worse in color.
This looks especially bad when zooming and panning because it creates these swirling patterns in the video.
a) What's causing this? Is it something I'm doing wrong when scanning?
b) What can I do about it? I.e. is there a filter I can apply in Vegas, or something different I can do when scanning?
Thanks.

Comments

jetdv wrote on 12/23/2003, 7:12 AM

When scanning, my scanning software has a setting for "magazine", "newspaper", and a couple of others in which it automatically takes care of eliminating the "dots" with which these images consist.

In Vegas, you my try adding a very slight blur.

TomHHI wrote on 12/23/2003, 7:22 AM

Most photo editing software has a function to remove "moire" which is the pattern created when scanning a printed photo as it is made up of dots. I have also done a slight defocus in phot editing which also tends to remove the moire pattern.

Chienworks wrote on 12/23/2003, 7:51 AM

A method i use that seems very effective in eliminating the dot pattern is to scan at a very high resolution, like 2400dpi or so, then reduce the picture to 1/10 size (10%) or so and set the resolution to 240. This blends the dots together into a much smoother image. It may need a bit of sharpening to make the edges crisp again, but not always.

Jsnkc wrote on 12/23/2003, 7:58 AM

Also if you scan the image, then rotate it slightly in Photoshop it will sometimes reduce it.

berenberen wrote on 12/23/2003, 10:38 AM

Thanks. I'm going to try some of the ideas offered.
What interesting, though, is that this pattern showed up even in a scan made from a high-quality print - a b/w printed in a coffee table book. Is that usual?

TomHHI wrote on 12/23/2003, 10:43 AM

Yes. If you look at the picture under a magnifying glass, you will see that unlike a photograph, it is made up of dots. The size of the dots is usually smaller in high quality prints such as coffee table books and very large in newpaper photos, but thay are all made up of dots and will result in the scans you see.

berenberen wrote on 12/23/2003, 4:09 PM

Thanks Tom.
Just out of curiosity, are photos different (i.e. without dots)? Because the dot effect doesn't happen with my scanned photos.

TomHHI wrote on 12/23/2003, 5:29 PM

Yes photos are different (unless printed on an injet printer). Photos are continuous tone, so the scan is picking up all the infoe not portions of dots that do not align wiht the ccd in the scanner.