I require a night vision effect for a project I'm working on, and I'm wondering whether a shader would be the way to go. To do this effect, everything on the screen would first need to be converted to grey-scale (black and white), and then mid greys would need to become bright green. The effect would also need to be switched on and off during the game in a split second. Could I do this with materials, or would a shader produce better results.

Thanks