Kit seems to have dropped off the radar, but hopefully someone can help me out here. As you can see, I had no problem achieving the pulsing effect (see Tutorial 3) with this photo...

But when I try to do the same thing with a completely white background, I get nothing but white as long as the background layer is visible. Here's what I get when the white background is made invisible.

What I want to do is put this image on the right edge of a white web page, repeating vertically, as if a vertical green lightsaber was semi-visible. If the web page background was black, I could use it as is, but I want a white page. Does this whole effect simply not work on a white (or very pale) background, or am I overlooking something? Thanks in advance for any help.