User's Manual

ADOBE PHOTOSHOP CS2
User Guide
289
To edit a combination of color channels at the same time, Shift-select the channels in the Channels palette before
choosing Curves. The Channel menu then displays the abbreviations for the target channels—for example, CM for
cyan and magenta. The menu also contains the individual channels for the selected combination. Keep in mind that
this method does not work in a Curves adjustment layer.
3 Add a point along the curve by doing one of the following:
• Click directly on the curve.
• (RGB images only) Ctrl-click (Windows) or Command-click (Mac OS) a pixel in the image.
Ctrl/Command-clicking pixels in the image is the best way to add points when you want to preserve or adjust specific
details in an image.
You can add up to 14 control points to the curve. To remove a control point, drag it off the graph, select it and press
Delete, or Ctrl-click (Windows) or Command-click (Mac OS) the control point. You cannot delete the endpoints of
the curve.
Ctrl-clicking (Windows) or Command-clicking (Mac OS) three areas of an image to add points to the curve. Lightening the highlights and dark-
ening the shadows is represented by an S-curve where the image contrast is increased.
To determine the lightest and darkest areas in an RGB image, drag over the image. The intensity values of the area
under the pointer, and the corresponding location on the curve, are displayed in the Curves dialog box. Dragging the
pointer over a CMYK image shows the percentages in the Color palette if it’s displaying CMYK values.
4 Do one of the following to adjust the shape of the curve:
• Click a point, and drag the curve until the image looks right to you.
• Click a point on the curve, and enter values in the Input and Output text boxes.
• Select the pencil at the bottom of the dialog box, and drag to draw a new curve. You can hold down Shift to
constrain the curve to a straight line, and click to define endpoints. When you finish, click Smooth if you want to
smooth the curve.
Points on the curve remain anchored until you move them. As a result, you can make an adjustment in one tonal area
while other areas remain unaffected.