Holography is different from 3D or Imax. Remember back to the very first Star Wars movie. Luke gets the two droids and he is playing with R2D2 when suddenly a holographic image of Princess Leia is projected. It was also used in the Iron Man movie.
3D vs. Hologram
With a 3D movie, it looks more 3 dimensional than with a regular movie. If you move around though, you still see the same thing. With the holographic image as you walk around it, you see different sides of the image. So in the Star Wars movie if you were to walk around the projection of Princess Leia, you would see for example first her left side, then her front, then her right side and then her back. It would be like you were walking around a real person.
It works by recording the light scattered from whatever you are creating an image of. You take a laser beam and split it and shine one part at the object or persona and the other part at the recording medium. The light bouncing back from the object is also sent to the recording medium and creates an interference pattern. This is then used to create the holographic image.
New York Holography Museum
There was a museum in New York City dedicated to holograms. They had a display space that was very small but very worthwhile seeing. It was somewhere near FAO Schwartz. In looking online there was apparently another museum or the main location for this one in Soho. Unfortunately it wasn’t able to raise enough funds to survive. It closed in 1992. The collection has been placed in storage.
There were some amazing images and walking around them like you were walking around the real thing (although without the correct colors) seemed like something out of the future.
Amazing Microscope Hologram
The most amazing image of all was the microscope. As I am walking by it, I thought it was interesting and then I had a brainstorm. If you can walk around an image like it is real, could you walk around the microscope and look through it like it was real?
I moved my eyes so that they were lined up like I was really looking through the microscope. Sure enough, you could see the image through the eye piece just as if you were looking through a real microscope. Once I did that and commented on it then everyone around me came to look through the microscope. I looked for other similar tricks in the other holograms but that is the only one I remember.
It turns out there was a holography museum in Chicago as well and it also went under but one anonymous donor paid to have the collection kept intact for future posterity.