Adjust the color, tone and alpha channels with the curves adjustment, either on individual channels or by adjusting the master curve.
Settings
The following settings can be adjusted:
Color space—select a color mode (Grey/RGB/CMYK/LAB) from the first pop-up menu.
Channels—specify a single color channel to apply the adjustment to, including the layer's alpha channel. Master (the default choice) applies the adjustment to all color channels*, excluding alpha channel*. Select from the second pop-up menu.
Spline—displays the curves spline chart which can be shaped to adjust the design's tonal range.
To adjust a curves graph:
On the curves graph, do any of the following:
Drag the curve to adjust the tonal range of the design.
Tap on the curve to add additional nodes.
Tap to select an existing node and drag to manipulate it.