Using these parameters, the glow effect takes the Z-buffer into account (i.e. the distance from the camera to each surface) or the glow is adjusted radially around an object.
The Start Range and End Range define a range over which the glow changes with distance.
There are two settings.
Start Range and End Range refer to the Z-buffer, i.e., the distance from the camera to the object’s surface.
Start Range and End Range refer to the position of the object’s axis in 3D space. The glow spreads out radially from the axis.
You can use gradients to refine the following glow properties from the Glow page: Size, Intensity, Luminosity and Color (see Glow entry).
Think of these gradients as running from the Start Range value to the End Range value. In the gradient, black represents a value of 0, white represents the value defined on the Glow page.