How might I diffuse light bulbs aimed towards a crowd so it still throws light well but doesn't blind them?

I have created a system where I use a red, green and blue light bulb to kind of create an "any color LED" effect using faders and whatnot. Now I was hoping to use it at a party to create general washes of light but I don't wanna blind people who look into it so i was hoping to diffuse the light and still get the wash of color I'm looking for. What kind of material would do that?