I have a 2D game and I wanted to apply bloom to the main GameObjects so I attached the effect onto the main camera, however the background also gets affected by the bloom and it gets all shiny. How can I make it ignore the bloom effect?
Bloom effect in Unity is actually a post effect which means it works after all the GameObjects have been rendered by the camera, and it can't be seperately affected.
The only way you can do this is use two cameras, one for the main GameObjects and one for the background, and properly set the layer and Camera's culling mask of the cameras
Check this doc for more detail http://docs.unity3d.com/Manual/Layers.html