It is so-called the Moiré Pattern! But do you know how those stripes appear on the scanned images?
“Moiré patterns are large-scale interference patterns that can be produced when an opaque ruled pattern with transparent gaps is overlaid on another similar pattern.” – That’s the definition from the Wikipedia.
The most common situation in scanning, a moiré pattern on the scanned image is created from scanning pictures in magazines, or printed material that use color dithering.
How to remove those annoying moiré pattern on the scanned image? It’s very easy, you just need to apply the “Descreen” function to remove the unsightly interference patterns which may occur when scanning newspapers or magazines.