This leaves me with the outlines and nothing else on that layer, as if had done my drawing on a piece of acetate. Of course, it will only appear that way if I click the little Eye Icon that's next to the Background Layer in the Layer's Palette. Doing that makes the Background Layer (with all of its white pixels) temporarily invisible so that I can admire my handiwork on the Outlines Layer.

When the Background Layer is visible, of course, (see above on the right), I can't even tell that the Outlines Layer has been added. It will make itself felt, though, as soon as I start adding color to my Background Layer.