The Contrast slider in Process 2012 operates in almost the same as the Process 2003/2010 one. Basically with a contrast adjustment as one side of the midpoint value is made darker, the other side is made lighter. So, an increased contrast adjustment will make the shadows darker and the highlights lighter. A reduced contrast adjustment will make the shadows lighter and the highlights darker. The Contrast slider behavior in Process 2012 does adapt slightly according to each image and should allow you to better differentiate the tone information in the tone areas that predominate. For low key images the midpoint is offset slightly toward the shadows, and with high key images the midpoint is offset toward the highlights (see Figure 4.29). Note that increasing the contrast in Lightroom does not produce the same kind of unusual color shifts that you sometimes see in Photoshop when you use Curves. This is because the Lightroom/Camera Raw processing manages to prevent such hue shifts as you increase the contrast.
Figure 4.29 Here, you can see the effective Contrast curve range for the Contrast slider. The top view shows the range for Process 2003/2010, where the midpoint was always locked. Below are representations of a Contrast adjustment in Process 2012, where the midpoint adapts according to the tone range bias of the image being adjusted.
Essentially, you’ll want to use the Exposure slider first to set the Exposure brightness and then adjust the Contrast slider according to how much the tones in the image you are adjusting need compressing or expanding. The remaining sliders can then be used to make further tweaks after these two initial image adjustments have been made.
One of the things that tends to confuse some people is the fact that as well as the Contrast adjustment in the Basic panel there is also a separate Tone Curve panel that can be used to adjust the contrast. Basically, the two are interlinked. The adjustments you make using the Contrast slider in the Basic panel are another type of Tone Curve adjustment. The thing to appreciate here is that when you go to the Tone Curve panel (where the default curve is now a linear curve shape), the adjustments you apply here are applied relative to the contrast adjustment that’s already been applied in the Basic panel. By always starting with a linear curve you have more flexibility in the Tone Curve panel to enhance the contrast of any image.