Color Cast Correction
Adjust the color of the image by selecting the individual channel you wish to affect and moving the midpoint up or down--depending on the cast you are trying to remove.
Make sure the info Palette is visible on your screen. If it is not visible, select Window, Info.
Adjusting the Image's Individual Channel Mid Tones
Go Layer, New Adjustment Layer, Curves. Make sure the Mode is set to Normal.
Curves Dialog Box Individual Channel Selected
Make sure the value readout is set to Ink Percentage. Make sure the Preview box is checked. Move the individual channel's mid tone point up to increase complement color. Move the individual channel's mid tone point down to increase the channel's color. Use the Kenly 3•6•9 Rule. You can check and uncheck the Preview box to see the effects of your mid tone adjustment.
Raise or lower the individual channel's mid tone point to correct the image's color.
Click OK once you have set the individual channel's mid tone.
Kenly 3•6•9 Rule
The Kenly 3•6•9 Rule gives guidance for adjustments in Curves. Developed by Eric Kenly, the rule states the following:
An adjustment of 3% is a minor correction.
An adjustment of 6% is a moderate correction.
An adjustment of 9% is a major correction.
Any adjustment over 9% suggests that the image should be recaptured.
These percentages work in both plus or minus ranges. Adjustments of +6% or -6% are both moderate.
On the next page we will compare the Individual Channel's Mid Tone adjusted image with the original.