Install reshade 3.0.5:
https://reshade.me/https://reshade.me/
Run the exe and install it where the main exe is which is here:
The Witcher 3\bin\x64
Now drop the ini file include in this archive and drop it here:
The Witcher 3\bin\x64
Load them game hit f2 + shift and add the provided preset to it and you can turn the effects on or off with the insert key.