Wave shaped lines on scanned image

I've searched the forums but could not find a similar request or answer.

When I scan an image (photo, or color graphic), the result shown in photoshop has 'wave shaped' lines all over it, wich aren't on the original.

What could cause this ?
I've tried scanning at different resolutions but that doesn't seem to change anything.

Is it clear what I mean ? If you want to see an example, let me know and I will upload it later today.

thx,

Hans

Sure. Let's see a sample.

Is it moiré?

< http://graphicssoft.about.com/cs/photoshop/ht/apsremovemoire .htm>