Norbert said:I beleive that many of the spells cast from that wand were probably overlooked and not represented simply due to the mad rush to produce what was IMHO the best chapters of the series so far... And the curse which produced the scar on Harry's forehead was one of them.
This is pretty much exactly how I feel. The shadows were there, we just didn't see them. Either cause JKR didn't take the trouble to write out a shadow for each and every spell, or some of the shadows were so slight that Harry didn't notice them and therefore we wouldn't know about them (since we see everything from Harry's POV). What would the shadow be for the Imperious Curse? We don't see that one. But we know the spell was done. There was no one killed when the curse was performed on Harry, so no shadow of a person appeared. Maybe a "wooshing" sound came out the wand, much like the screaming sounds that represented crucio, and there was just so much going on that Harry didn't hear it. Or maybe green light did, but there was so much other light that Harry didn't notice it. Just because it wasn't directly "spelled out" for us in the book, doesn't mean it didn't happen.