Quote:
If the cameras picked up the rest of the ride, why wouldn't it pick up the HHG?
Actually, the cameras for the Osmonds TV program mostly didn't. If you compare the Osmonds ride-through with the Super-8 souvenir HM reel, it's clear that they just reused this stock footage for all of the tough lighting shots. That footage is really, really, early, maybe even before opening day. It includes shots of the ghosts entering the ballroom that are actually shots of the scale model! I'll bet it was shot by WDI under carefully controlled lighting conditions for in-house use in evaluating the ride, and later edited down for the souvenir reel.

As for the appearance of the wispy ghosts, like I said, they greatly resembled the wraiths fluttering up the scrims in the graveyard. No faces. Having now seen the wavy screen in the old blueprint, what amazes me is how simple the effect probably was. I suspect that the three projecters had slowly spinning cylinders or wheels with slides of the ghosts on them (like the rain effect in the windows of the changing portrait hall, and like the graveyard wraiths). The waves in the screen made them appear to undulate as they glided by. The fact that the interior of the doombuggies is much brighter than the outside of them when you look in the mirror ensured that the dim ghosts would only be visible around the outside of the buggies, but not inside with the passengers, because they were simply washed out there. Those are my theories, anyway.