The pattern produced on a photosensitive medium that has been exposed by holography and then photographically developed.
The photosensitive medium so exposed and so developed. Also called holograph.
In other words..
It's plasma...that cant pass through matierals...but materials can pass through it
you'd have to have nothing at all blocking it
Dude! Did you hear about the new internet coming soon?? It will be made up of holograms!