For some reason, whenever I make an object dissolve away, the spots that should be empty are being replaced with whatever the 1st color is, making a flat color background instead of nothing. After setting the edge to 0, it turns out that the problem is that it isn't actually dissolving the sprite at all. The effect works properly in terms of the dissolve look, but it's only affecting the sprite's color without changing the alpha from 1 to 0. It works properly when dissolving objects back in, but not when dissolving them away.