To adjust brightness curves
1
Select one paint object to adjust. The paint object can be in edit
mode. You can select an area in the image. If you dont make a
selection, the entire image is affected.
2
Choose Image > Adjust > Curves.
3
In the Channel pop-up menu, select the composite channel or
an individual channel to adjust. To adjust multiple channels, select
the channels in the Channels palette first.
4
To change the shape of the existing curve, make sure the curve
button at the bottom-left is selected.
Click points that you want to keep the same
Drag points on the curve that you want to change. Or, enter
values in the Input and Output boxes. For example, to keep
midtones the same, click the center of the curve, then drag
other areas of the curve. To adjust midtones without affect-
Curves dialog box
The graph shows how Canvas
maps input brightness values
to output values. Select Pre-
view to see the effect on the
image.
A
Choose a channel to adjust.
B
The grayscale ramp shows
the lightness scale, either 0-255
(dark to light) or 0-100 percent
(light to dark). Click the ramp to
reverse the scale and the curve.
C Type brightness values in
the Input and Output boxes.
Or, drag the pointer (circled) to
specify brightness values. Here,
pixels of 157 brightness are
lightened to 171.
D Click this icon and drag a
point on the curve to reshape
the curve. Click the curve to add
up to 19 control points. Drag
points off the curve to delete
them.
E
To draw a disconnected
segment, click this icon and
drag in the graph.
F
With the pencil (E) selected,
click to smooth the curve.
C
Input
A
B
F
D E
Tip
To redraw the curve complete-
ly, or to create sharp changes
in brightness for a tonal range,
click the pencil and draw a new
curve or segment.