Photoshop Tutorials - Color Balance. Selective Color
Selective color correction option is typical for professional scanners and color separation programs that allow changing the parameters of selected colors of additive and subtractive color models. Selective Color correction is based on the table below:
This table displays the percentage of the polygraphic paint needed to print every color component of additive (RGB) and subtractive (CMYK) color models. Increasing or decreasing the values, you can change one component without influencing the others. This option is usually applied when, for example, you need to reduce the deduction of the cyan component in green, but keep it in blue component.
As other color correction commands, Selective Color helps to correct the color disbalance and improve the image quality.
In the Colors dropdown menu you can select one of the components of CMY or RGB, and black, white and grey colors. The parameters of selected color range are edited with four sliders, respective to components of CMYK color model: Cyan, Magenta, Yellow, Black.
Under Method, you can choose Relative or Absolute method of color correction.
Relative method changes the current value of the color model CMYK by percent of the reference value. Therefore, when you add 10 percent to the 50 percent value of the color; the result will not be 60 percent; it will equal 55, because 10 percent of 50 equal 5. You can not edit white color with Relative method, as it does not have any components.
Absolute method of correction adds or removes the absolute values of CMYK components. When you add 10 percent to 50 percent it equals 60 percent.