Question Apply Shader Graph to Camera

Hello there, I am new here so I apologise if this is not the right section. I started using Unity 2019 a few days ago and have been messing with the new Shader Graphs and the visual interface. I was able to apply the graph as a material to a game object, but was wondering if it was possible to instead apply the shader globally to the main camera. For example if there was a visual noise effect I want to apply that to my main camera in addition to the preexisting Post-process Volume stack and settings I have.

 

Same here I created black hole shader graph and been trying to apply it to camera since few days and all tries fails.
I thought assigning the shader graph to material then creating a script attached to camera and applying it using those codes:

Code (CSharp):

1. void OnRenderImage(RenderTexture source, RenderTexture destination)
2.     {
3.             Graphics.Blit(source,destination, _material);
4.  
5.         }
6.     }

but seems OnRenderImage not being called at all.