I have the following image created in Gimp.
I'd like to create a similar image in Inkscape. What I want to happen is to have a bright light source and I want this light source to brighten the circles having the most intense effect at the edge of the blue circle.
In Gimp I'm able to achieve this by having a white to black gradient as separate layer on top and setting the blend mode of that layer to addition
(using the technique in this tutorial: http://gimp-tutorials.net/gimp-glow-effect)
How can I achieve a similar effect in Inkscape?