i'm not an expert, and i rarely touch any preset, but i think you can do thins from lift gama gain. RGB=red, green, blue colors, so 1rst option inside the float3() is red, 2nd is green, and 3rd is blue. i think the option you need is midtones or gain(as i said i'm not an expert). put your game in window mode(but don't minimize it), open the preset and do some tweaks(increase it by a lot-not just by 0.05- to easily see the change), then save to see what happened. remember to make a back-up before you start tweaking