Disable post process/tone map in BG matte painting

I am working on a movie that uses 2.5D matte paintings as a background, and need to combine this with fully rendered foreground 3D assets.
Thus far, I have been unable to render from the sequence editor in such a way that my matte painting gets output without any tone mapping or tone curves. I do want to render out all the foreground geometry with all the tonecurve and tone mapping applied but I want to keep the unlit background geometry looking exactly like the texture map looked in photoshop.