Screen and postprocessing shaders arent doing anything

I’m quite new to shaders, so I’m really sorry if this question seems kinda basic. I tried following this tutorial Postprocessing and image effects in Unity - Shader Tutorial to add either of the two postprocessing effect, but neither seem to do anything. I wrote the shader script in the shader object that I created, and C# script is well…a C# script. Then I added the script to my main camera objects. Do I have to do anything else or am I missing something, because nothing is changing either way. I should note, that I tried this in both Unity 4 and 5, if that matters.

Also, could this be related to the fact that I don’t have the pro version of Unity, or does that even change anything?

Thanks in advance!

In Unity 4 you’ll need a Pro licence to use image effects. For Unity 5 any licence will do. Having created and attached the effect, you are clicking play and looking at the game view, right?