What it isLUTs (Look Up Tables) are in this case color palettes which are used to recolor the game. It is integrated by Ganossa of the ReShade Team. Think of it like a cheat sheet where ReShade looks at - when it comes to color choosing. If you are curious about the topic you can find more information here for example. It is easy and fun and enhances the game visually like you want! Try them out!
How to install
You´ve downloaded Real Light V7 already right? Now you copy or extract your chosen color scheme .png into the following folder: steamapps/common/Arma 3/ReShade/Shaders/Ganossa/Textures.
Now go into the file at steamapps/common/Arma 3/ReShade/Presets/Real_Light_V7/Shaders_by_Ganossa.cfg and change the name of the palette at line 110
#define TuningColorLUTDstTexture "rl7.png" to
#define TuningColorLUTDstTexture "your chosen color scheme.png"
and save the file. Done!
Retab or start the game and ReShade should reload itself and apply the new scheme immediately.
If it doesn´t apply the new scheme after tabbing back into the running game - try to fill in some blanks or tabs in an empty line and save it again. If the file size changes by that ReShade will reload itself for sure then.
If you want to reduce the intensity
Browse to the ReShade folder in your main game folder.
Open Shaders_by_Ganossa.cfg and go to line 107:
#define TuningColorLUTIntensityLuma 0.67 //[0.00:1.00]
Here you can play with the values. Luma is for brightness and Chroma is for the colors.