Tuesday, September 24, 2013
This often misunderstood control is as much about brightness as contrast
I recently read one popular author's introduction to his chapter on the Lightroom Tone Curve, and he started out by saying that with the improvements in the 2012 Process Version, the Tone Curve was basically outdated. Nothing could be further from the truth. It's true the Lightroom 4/ACR 7 update represented a complete overhaul of the Basic tools that gave us much more powerful Highlight and Shadow correction. That update also eliminated at least one control (Brightness) and reconfigured everything else in the Basic panel to be more symmetrical, starting from a zero position in the middle and having the ability to move them in either direction.
Wrapping your head around how all the controls work does require some study, testing and exploration. But no matter how sophisticated the new controls have become, the bottom line is that the much misunderstood Tone Curve still provides a very different—and crucial—type of control over your tonal correction. I say that it's misunderstood because beginners seem to assume that the Tone Curve only has to do with the brightness of various tones and don't yet understand that it's as much about contrast as it is about brightness. With the Tone Curve, the two go hand in hand.
When the line is straight, an input value of 50% (middle gray) will have an output value of exactly 50%, too. Roll your mouse right over the middle of the graph on the line, and you'll see two numbers appear in the upper-left corner. If you're able to get your mouse exactly over the center of the graph, the values will read 50/50. Click down right there, and drag straight up. (You can only click and drag directly on the Parametric Tone Curve in Lightroom. ACR's implementation of the Parametric Curve doesn't allow clicking directly on the graph, only on the sliders. Also, in ACR, you only see input/output values in the Point Curve.)
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