In addition to the histogram, one of the most useful tools for checking your exposure in Adobe Photoshop Lightroom 5 is the Show Clipping option. You can toggle it on and off in the View menu or with the keyboard shortcut “J”.
Show Clipping identifies shadow and highlight areas at the extreme ends of the range where your current exposure adjustments are causing details to be lost—pure black and pure white. When Show Clipping is enabled, blown-out highlights are shown in red and blocked-up shadows are shown in blue.
The conventional thinking is that you don’t want to lose details at the extreme ends of the tonal range, so you use this tool to correct your exposure until the red and blue indicators disappear. Contrary to that thinking, dramatic black-and-white photos will have some areas of pure black and pure white. You can break the rules and use this tool to process your way to black-and-white images that pop in just a few minutes.
Compare the two images below to see the difference in visual impact. The first image is what Lightroom’s automatic tone adjustments delivered. To me, the image looks flat, if technically well exposed. The second image is what I arrived at with a few quick adjustments using Show Clipping as my guide.