alt Hacker News> if you cut it (the film media) in half, you have two copies of the hologram.
A hologram is much like a window, you can look through a big window or a small window, and see what's at the other side both times, but the big window still gives you a lot more viewing angles than the small one. Cutting a hologram in half gives you half a hologram, not two copies of the hologram, it's just that you can change your viewing angle to still see what's on the other side, but that will be a different image than with the full hologram.
I remember as a kid having one of the Usborne books (80s) very badly illustrating this, and it gave completely the wrong idea about what you got; one chopped up hologram from a magazine later and I was sadder and wiser.
You get pretty much what you would naively expect from chopping up a hologram before reading that kind of misleading "two copies" text: exactly the same view of the object as you had from that part of the hologram before you cut it up.