One of the best ways that people hardly ever think of is to use the ditherbox. Just paint a pattern (like 2 black pixels in the top, and two white under it), fill the pic with it, and then fade it.
There you go, perfect scan lines.
"Stephen Wolfram is the creator of Mathematica and is widely regarded as the most important innovator in scientific and technical computing today." - Stephen Wolfram
"Stephen Wolfram is the creator of Mathematica and is widely regarded as the most important innovator in scientific and technical computing today." - Stephen Wolfram
The only image I've done a TV filter on was for a subsite of mine... Hellhive, part of Jigoku.
Eh. It's easy enough to do. A 2x2 BW image. Top two pixels black, bottom two white. All you have to do is bucket fill this pattern into a separate layer of the image, and set it to Multiply. Then you play with the opacity slider of the layer to control how strong the dark lines are. When you get it to the level you want, there you go. You can blur it a bit if you want, but that might require a larger line pattern from the start to look right. Also, I suggest ramping up the brightness of the image under the lines so it will maintain a decent average brightness level instead of looking dulled down.