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Using the Histogram Tool with the Curves Option

You can use an alternative version of the Histogram tool to make it work more like the Curves tool in Photoshop.
The Curves option lets you selectively stretch or compress input tones to change the resulting output tones. Tones stretch as the slope of the curve increases, and compress when the slope decreases (compared to the original diagonal line). Compressed tones have less contrast, and stretched tones have more contrast. You can use many vertexes to control a tonal curve. A diagonal line through the center leaves tones unchanged.
An S-curve adds contrast to mid-tones at the expense of shadows and highlights. An inverted S-curve does the opposite.
You cannot add contrast in one tonal region without also decreasing it in another. The Curves option essentially redistributes the contrast. Unless you create curves with negative slopes, tones that were brighter originally remain brighter after you apply the curve, but the amount of brightness changes, depending on your edits.
Abrupt changes in slope can produce posterization. Moderate adjustments may work best.