How Do Three D Films Work?

With these glasses, rather than having two sets of the same image projected on a movie screen simultaneously, you only have one set displayed at any given instant. They are kind of like very tiny window blinds that open and shut at an incredible speed. This approach helps correct a problem that a lot of other three d films have, which is that they tend to be pretty dark. And it's all happening fast enough that our brains can't detect the changes. To us, it just seems like a continuous series of images coming right into our brains."