1. Make a 800 (or shorter)x2 workspace
2. Choose the pencil and make sure the color is black
3. Choose 1pt for the size of the pencil
4. Make a straight line by pressing shift and dragging the pencil.
Make sure that you made half black and half white
5. Go to edit>Define Pattern
6. Give a name "line" (or anything you want)
To apply this to work:
1. Make a new layer for your scanline
2. Go to edit and click on Fill
3. On the "use" combo box go to Pattern
4. Choose your line
5. Click ok
If you still have questions, drop me a line and I'd be happy to help.
