Change the transparency of the center of the shadow
A semitransparent shadow is more realistic than a solid shadow. You can change the transparency of the center of a shadow; the outer edge is always totally transparent.
 To change the transparency:
 To change the transparency:
1. Select the object (see Selecting objects). (See Notes.)
2. Choose the Shadow Tool.
3. On the Shadow Tool Infobar either drag the Transparency slider or type a value into the text box on the right.
Notes:
 You can also use the Shadow Tool 
 to select objects - more details.
 You can also use the Shadow Tool 
 to select objects - more details.
 You can profile how the transparency 
 level changes across the blur. See Changing 
 the shadow profile.
 You can profile how the transparency 
 level changes across the blur. See Changing 
 the shadow profile.
 If you have several shadowed objects 
 selected, any changes apply to all the shadows.
 If you have several shadowed objects 
 selected, any changes apply to all the shadows.
 The shadow is always more transparent 
 than the object casting the shadow. For example if the object is 50% transparent, 
 then the shadow can be 50% to 100% transparent.
 The shadow is always more transparent 
 than the object casting the shadow. For example if the object is 50% transparent, 
 then the shadow can be 50% to 100% transparent.
Movie—click below (not working in this version)