I'm unable to use a UI image blur effect when I'm also using a grayscale post-processing effect on my camera.
I activate the grayscale post-processing effect when the game is paused, which is also when I show my pause menu, which is a UI panel with a blur shader.
When the grayscale effect is enabled, the UI panel is invisible. It's there, because all my text/buttons show fine. It's just the portion the blur shader applies to, has become fully transparent.
When the grayscale effect is disabled, my panel shows fine, with the blur working as expected.
Here is the grayscale post-processing effect I'm using by Alan Zucconi. I have this on my Main Camera, and it is enabled when my game is paused.
Here is the blur shader I'm using by vinipc, modified from cician, whose blur shader is commonly used by Unity users.
I'm not sure why these would conflict. My guess is that somehow the blur effect is seeing empty/fully transparent colors and therefore is also transparent?