Dpi

[Howdya do that]

I am having trouble with the quality of the pictures I get when I scan photos from old newspaper articles. Can anyone tell me how DPI (dots per inch) a newspaper photograph usually is so I can set the scanner the same:?

[zenwood]

I'd suggest going to at least 600 dpi or higher. You want to scan at higher resolution (dpi) than the dots per inch in the newspaper picture, otherwise the dots in the picture interfere with the dots of the scan resulting in strange patterns (due to an effect called aliasing).

After you've scanned the picture, you may be able to use some software to smooth the image and subsequently reduce the resolution, if you need to.

[Grunt]

Yup, maximum DPI for scanning.

You'll never get great pictures from scanning newsprint. It's pretty poor quality to start with.

[Ruddigar]

You'll never get great pictures from scanning newsprint. It's pretty poor quality to start with.

It's not just the quality of the print that's poor. The articles are usually pretty lousy too. :no:

[Howdya do that]

Thanks Zen,

You were spot on the money. I was getting funny patterns but didn't know how to explain it.

Ruddy, I didn't know you were a journalist as well:D

[zenwood]

They're called Moire patterns. There are lots of google hits on how to remove them, but it's easier to eliminate them from the start using high-res scanning.

Note: you may see moire patterns on your screen, without them being actually present in the scan. This will happen due to the interaction of the dots in the image with the pixels of your screen. Test for this by zooming in. If you see the individual dots when you zoom in, then your scanning resolution was high enough.

Here are some gory details:

http://www.wfu.edu/~matthews/misc/DigPhotog/alias/index.html (http://www.wfu.edu/%7Ematthews/misc/DigPhotog/alias/index.html)

[Honorary Bloke]

I am having trouble with the quality of the pictures I get when I scan photos from old newspaper articles. Can anyone tell me how DPI (dots per inch) a newspaper photograph usually is so I can set the scanner the same:?

Wot Zenwood said. Standard newspaper photos are 72 DPI--quite low-res and dodgy. Hard to get any decent results, even after scanning. :(

[chrisb691]

They're called Moire patterns. There are lots of google hits on how to remove them, but it's easier to eliminate them from the start using high-res scanning.

Note: you may see moire patterns on your screen, without them being actually present in the scan. This will happen due to the interaction of the dots in the image with the pixels of your screen. Test for this by zooming in. If you see the individual dots when you zoom in, then your scanning resolution was high enough.

Here are some gory details:

http://www.wfu.edu/~matthews/misc/DigPhotog/alias/index.html

Thanks for the link, I can now understand some of the weird scan results I've had at times. :2tsup: