In this section, I can only hope to give you a flavor of what is possible with SVG filters. However, I think that I’ve provided enough to whet your appetite to spend time experimenting with them. Certainly, some impressive visual effects are possible.
The <feGaussianBlur> filter primitive defines in Listing 7.8 a generic filter you can use. In the first <use> element, you adjust the opacity of the Gaussian blur to 0.4: