Adjust > Curves
The Curves filter allows you to adjust the individual RGB (red, green, blue) and HSB (hue, saturation, brightness) values of your image. Use the points on the graph to adjust the relationship between the input levels (RGB and HSB values of the original pixels) and output levels (RGB and HSB values of corrected pixels). At the lower left of the chart, all values are zero. At the upper right, the RGB values are 255 and the HSB values are 360 for H and 1 for S and B.
1. Do one of the following:
 Choose Adjust > Curves
Click the Curves button
2. Use the following options:
Color Model
Use this option to choose the RGB or HSB Color model.
Use this option to edit the red, green, and blue channels. Choose Red, Green, or Blue to edit the individual color channels.
This option allows you to edit the hue, saturation, and brightness. Choose Hue, Saturation, or Brightness to edit the individual color components.
This option allows you to create a smooth curve in the transition graph that passes through all the control points.
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