After having started playing the Witcher 2 again I have developed this ReShade preset for my own use during gameplay. It is fairly performance intensive, but for this old of a game that shouldn't be much of a problem for anybody, if it is, I'm sorry. I will not make a performance version. 

Shaders need for this preset include:
Bumpmaping.fx
dh_uber_motion.fx
dh_ambient_remove.fx
dh_uber_rt.fx
AdvancedAutoHDR.fx
FGFXLargeScalePerceptualObscuranceIrradiance.fx
qUINT_mxao.fx
PD80_03_Shadows_Midtones_Highlights.fx
MartysMods_SOLARIS.fx
MartysMods_REGRADE.fx
qUIINT_bloom.fx
MartysMods_SHARPEN.fx
MartysMods_SMAA.fx
FXAA.fx
EyeAdaption.fx
Deband.fx
qUINT_deband.fx
UIMask.fx
DOF.fx
CinematicDOF.fx

There are sometimes multiple effects that run alongside each other (DOF, debanding, bloom, etc) this is intentional, some of them have hotkeys already set so you are able to quickly and easily toggle them on and off depending on the gameplay situation. Banding is a bad problem in some foggy areas so I turn them on there but off when I want view distance maximized unchanged by the debanding files. The Cinematic DOF can be quite subtle, you have to look close in some of the screenhsots. View images for toggle keybindings.

This preset is my own preference, I figured I would upload it here as there are not many ReShades for this game here, and I am quite happy with how it turned out. 

UPDATE 0.6
Edited preset for lower exposure overall, Added uimask for HUD visibility (3840x2160), Changed primary DOF shader to MatsoDOF from a combination of RingDOF and CinematicDOF for overall better performance.

Install like any other Reshade preset.
Copy my Realematic.ini into the bin folder within Witcher 2 Directory
Install Reshade (this was developed on 5.9 as I'm using the DXVK mod for witcher 2 and that was the last version to support Vulkan I believe)
select Realematic.ini as a preset to use
The installer should from there select the necessary shaders
Copy my Reshade.ini and overwrite the existing one in Witcher 2 directory (I have edited the depth in game to optimize the effects of this preset)
When the game launches select my Realematic preset from the dropdown menu

I have an issue with the depth buffer does not always select the correct line, make sure by going to the Add-ons tab and selecting the line that matches your resolution.

Happy gaming.