You need anaglyph glasses (glassses with color filters for each eye). Do you mean RED and BLUE? I've never seen green and purple before.
That said, anaglyph is the cheapest, lowest form of 3D viewing out there and I don't think I would watch a whole movie using that method. There used to be other much better methods but Vista was the last nail in the coffin for 3D 🙁.