Effects On An Entire Scene

I am trying to create some effects that change an entire scene. In the case that i need i need everything to be blurred and a ghost effect. I would assume that for the ghost effect i would need to get what rendered during the last frame, overlay that on the camera, and then change the alpha. But i dont know where to begin on that. Any help would be appreciated.

P.S. Sorry for the vague title, i wasn’t entirely sure how to phrase it.

Look into Image Effects http://docs.unity3d.com/Manual/comp-ImageEffects.html

A Camera Motion Blur can probably achieve the effect you want. Camera Motion Blur