The Color Balance command in the Adjust section of the Image menu allows you to make adjustments to colors by altering their position in the Red Green Blue (RGB)/Cyan Magenta Yellow (CMY) color scale.
Each of the colors is linked with its complement on the color scale, for example, Cyan with Red, and connected by an adjustment slider. The Color Levels boxes just above the sliders display the current color values, reading from left to right, for the top, middle and bottom sliders respectively. The range of possible values lies between -100 and 100. The default is 0. Note that your adjustments should usually be small i.e. within about 5 units either side of 0, so that the color balance is not radically altered.
In the "Color Balance" dialog you can adjust the colors as follows:
Color is added (or subtracted) by moving the slider towards (or away from) the color to be added (or subtracted). So, to add green move the middle slider towards the green end of the Magenta/Green scale. To subtract blue move the slider away from the blue end towards the yellow end of the Yellow/Blue scale, this in effect being the same as adding yellow.
There are three Tone buttons which allow you to concentrate change over approximate tonal ranges in the image. The selected button guides the changes towards the relevant tonal range, hence helping concentrate the changes. The tones are:
Shadows for tones over 75%
Midtones for tones between 25% and 75%
Highlights for tones below 25%
The Preserve Luminosity button helps keep the current luminosity - or lightness - of the image. When this is unchecked the tonal values of the image are altered along with the colors.
The changes you make will be implemented while you are still in the dialog. Click on Cancel if you want to cancel these; otherwise click on OK to keep the changes and close the dialog.
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