To better understand color cast and how to fix it we need to go back to the color wheel basics. Without going into too much detail and fancy rgb formulas, all digital cameras use some type of RGB formula to define the colors they capture to form an image. RGB simply explained means that when adding the exact same parts of red, green and blue will produce white and the absence of colors produces black.
Warm Colors: Magenta - Red - Yellow
Cool Colors: Blue - Cyan - Green
In Photography Warm Colors are Pair with their counterpart Warm Colors, meaning Blue pairs up with Yellow. Magenta with Green and Red with Cyan. So when you remove Blue from your image you are adding Yellow and when you add Red you removing Cyan and when you add equal parts of each counterpart you have neutral.
Warm colors will always neutralize cool colors and the key to learn how to color correct your images is to learn which color neutralizes the other. For example if you have an image where you have a green color cast due to your subject being sitting on the grass, you want to color correct that image by adding magenta thus removing green.
Here are a couple of examples on different ways to fix Color Cast.
In this image there was a green color cast due to all the greenery, by adding a Magenta Photo Filter I have removed the overall green cast. Before (top image), After (bottom image),
In this image my subject was too red due to the blanket it was laying on, by adding a Cyan filter I fix the color cast. Before (bottom image), After (top image).
Color Cast can be fix using different techniques in Photoshop, you can use Photo filters like I did above, you can make adjustment layers and fix the color cast by adjusting each rgb color and they are many other ways.
The reality is that color balance in photos comes to personal preference, some photographers like more pastel colors while others prefers rich colors it also depends on the type of photography for example landscape and portrait photography where color balance might change to achieve a certain look or feel.
Patty Schmitt is an Award Winner & Published Photographer residing in the Wayzata & Twin Cities, MN area. She specialises in fine Art Portrait & lifestyle photography.