I was trolling through Disney's patents earlier, and I came across an item that I thought might be interesting to those hoping for a return of the Hatbox Ghost. I've seen some discussion on here of how WDI might update the technology in order to make the effect work, since the original used a spotlight turning on and off, but wasn't convincing. This line from US 7,236,301 B2 seemed to strike a chord:
The patent discloses a system using a polarized sheet behind a scrim and a spotlight with a activatable polarizing filter, such that you can't see through the scrim normally, but when the filter rotates into place, suddenly the light can get through to illuminate the object within...which might be a skull:BACKGROUND
Special effects designers may be required to make an object appear hidden (disappear) or visible (appear) to an observer on cue. For example, an amusement park having a haunted mansion may desire to make an object, such as a ghost, mysteriously appear and as just as mysteriously disappear to an observer. One conventional approach involves a projection system having an electromechanical means for directing light at and redirecting light from an object. However, this approach may not to an observer make an object disappear or reappear because such electromechanical means requires a finite time for turning on and turning off a light source illuminating the object. Furthermore, this approach may not smoothly nor in a controllable manner transition from hidden to visible an object to an observer on cue
The first application on this patent was dated 2003 - I don't know how that corresponds with the internal Hatbox timeline, so it may be unrelated, but I thought it was definitely interesting one way or another. There's a bunch of other cool ideas in there too, like having walls that look normal until you shine a special flashlight on them, and suddenly you can see something behind them.In another aspect, textured surface 30 may be a theatrical scrim. For example, the theatrical scrim is a material having a wide weave with part of the material being at least partially transparent to light. In this aspect, as source polarizer 40 is rotated while directed at the theatrical scrim, the hidden object transitions from a nearly invisible state to, for example, a nearly full visible state.
In yet another aspect, the surface of the theatrical scrim may contain a printed image. In one example, the printed image is a face. In this example, object 10 is a skull. By illuminating the printed image with light source 50 using source polarizer 40 parallel to transmissive axis 25 of polarized window 20, the skull is visible to an observer. Alternatively, changing the polarization of source polarizer 40 parallel to reflective axis 35 of the polarized window 20, the skull is invisible to an observer. In the invisible state, the observer sees the printed image of the face. In the visible state, the observer sees a composite image of the printed face and the skull.