What do interlacing artifacts look like?

[kinneera]

I've heard de-interlacing discussed a lot, and I was just wondering...how do you know when your video needs to be de-interlaced? What exactly do you see in the image?

[Darkbird]

You can see it on the edges of moving objects. It will be a a slightly offset "shadow" or fringe of the object with only half the scan lines present. It's showing the field lines from where the object used to be in time.

[hitechjunkie]