1. Go here and download FXAA_PPI_Rev_37.zip:
http://www.assembla.com/spaces/fxaa-pp-inject/documents#
2. Extract all the files from the "DirectX10" folder, from within the zip, to C:\Program Files (x86)\Origin Games\Battlefield 3 or wherever your BF3.exe lies
3. As of right now: external FXAA, sharpening, tonemapping, technicolor, and sepia are all enabled
4. In order to disable and customize all of these different filters....open up injFX_Settings.h (in notepad or wordpad) from within your BF3 installation directory.
5. You should see a section named "Filter Selection". Right under that, you should see a list of filters:
#define USE_ANTI_ALIASING
#define USE_PRE_SHARPEN
//#define USE_BLOOM *NOT WORKING
#define USE_TECHNICOLOR
#define USE_TONEMAP
#define USE_SEPIA
//#define USE_VIGNETTE
#define USE_POST_SHARPEN
//#define USE_FINAL_LIMITER
6. To disable a filter: put "//" (without quotes) in front of the filter you want to have disabled.
For example, if you want to disable sepia...find "#define USE_SEPIA" in the "Filter Selection" section and put "//" in front of it so it looks like this: "//#define USE_SEPIA". Sepia is now disabled
7. If you want to re-enable, then just delete the "//"
8. Right off, you want to disable "TechniColor" because it adds a washed out/bleached effect to the game by default.
9. What you want to focus on is the "Tonemap" section which has contrast/gamma/saturation...etc etc.
10. For color correction, you want to focus on "#define FogColor float4(0.08, 0.28, 0.10, 3.0)" under the "ToneMap" section. The 1st decimal number controls the amount of blue. 2nd = red. 3rd = yellow. 4th = white
11. You can adjust any setting in "real-time". To see the effects of your changes immediately...just alt-tab out of BF3, make a change, then go back to the game and you should see the changes. *This doesnt work with windowed mode.
Make sure you turn off POST PROC AA in BF3 to make sure that you dont get a double dose of FXAA which will make your game even blurrier