Color Balance Adjustment with Levels

[admin]

If you have an image that has a slight color cast to it, the Color Balance option in Photoshop is generally your best option to rectify it. It definitely is the easiest option to use. But sometimes you may feel a need to go beyond what it is capable of, and for this there's always Levels. We've looked at the power of Levels before. They're great for optimizing contrast. But when operating on individual channels rather than the image as a whole they can be used to adjust color balance and correct color casts....

More... (http://www.earthboundlight.com/phototips/color-balance-levels.html)