Tonemapping and Antialiasing?

For a project I am currently working on I have run into a problem involving the filmic tonemapper that ships with unreal (I’m in 4.22.3). We have a SceneCapture2D whose RenderTarget is piped directly into an unlit material and applied to a plane. Despite being unlit it appeared washed out and darker than it should have due to the tonemapper. As a workaround to that we created a postprocess material set to “replacing the tonemapper” that simply took PostProcessInput0 and sent it directly to the output. This fixed the washed out problem, but seems to have disabled anti-aliasing which makes other aspects look worse (especially the images captured by the SceneCapture2D). Any advice on how to proceed would be much appreciated.

before and after replacing the tonemapper.

the material we replaced the tonemapper with.

png exported from RenderTexture before replacing the tonemapper.

png exported from the RenderTarget after replacing the tonemapper (note the extreme aliasing)

Hi, I am experiencing exactly the same problem. Did you have any luck with this?

Here is how it looks in my case, when compositing a tree over a background image:

png exported from RenderTexture before replacing the tone mapper (note the washed-out colors).

png exported from the RenderTarget after replacing the tone mapper (note the extreme aliasing).

In the FAQ section of the Post Process Materials page in the documentation, there is a question:
I need to use "Before Tonemapper" to get proper TemporalAA. When I use a color, it is tone mapped and therefore looks different. How can I prevent that?
With the answer:
There is no easy solution. You would need to do an inverse tonemaping operation (expensive). The color also might appear different depending on eye adaptation. You could expose the EyeAdaptation level to the SceneTextures to compensate for that.
So, how do I execute the “inverse tonemapping”? I use fixed exposure settings and I am fine with suboptimal performance.