Steve while a rote approach will work sometimes, and most images will benefit from the application of an S curve, you need to tie what you adjust directly to points on your image. if you lower a point on the curve you will darken that point in the image and maybe lose detail in shadows, if you raise a point you will lighten that point in your image and maybe blow out detail. If you steepen a curve betwen 2 points you will increase contrast and separate colors more, if you flatten a curve, the reverse happens. Many of the tools in CNX2 are carryovers from CNX and are standard tools that you will find in most post processing SW. But making use of color and control points is actgually a much better way to adjust your images as you can control size, hue, saturation, brightness, contrast, red, green, blue, and warmth, all at one point.