it's photoshop 5.5. i don't use filters...just because i never really needed to. anyways, the effect is scanlines. my way is to make a 2x2 pixel image. fill one half of the image in black, and the other white.
goto edit>>select all. then edit>>define pattern. then you make a new image, a new layer, and use the paint bucket fill to color in the layer. set the layer opacity to about 25-35%, and you'll be good to go!
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