Apple Color 1.0 - Manual (Page 195)

Chapter 9 Primary In 195
An Example of the Luma Curve in Use
The following example illustrates how to make very specific changes to the contrast of
an image using the Luma curve. Looking at the waveform in the following image, you
can see that the sky is significantly brighter then the rest of the image. In order to bring
viewer attention more immediately to the subject sitting at the desk, you would want
to darken the sky outside the window, without affecting the brightness of the rest of
the image.
1 Before making any actual adjustments, pin down the midtones and shadows of the
image by adding a control point to the curve without moving it either up or down.
Adding control points to a portion of a curve that you don’t want to adjust, and leaving
them centered, is a great way to minimize the effect of other adjustments you’re
making to specific areas of an image. When you add additional control points to adjust
the curve, the unedited control points you placed will help to limit the correction.