Photoshop - White Balance Basics

 A white or gray object in a scene takes on the color cast by the ambient light or flash used to shoot the picture. Cameras don't always see color the way our eyes do and light bulbs can cause color casting problems as seen in the photo below.

There are some handy tools in the Camera Raw Filter in PS CC. Simply go to Filter > Camera Raw.
Use the White Balance tool  to specify an object that you want white or gray, Camera Raw can determine the color of the light in which the scene was shot and then adjust for scene lighting automatically. In this example, I selected the eye dropper tool then click on the ceiling which I knew should be white or neutral color (gray).

Here are the results.

Photoshop removed color that shouldn't be there and the room appears the same as when I was viewing it.
You can always use the Auto feature to let Photoshop read the Metadata that came with the image.

You can get good results by using this tool too.
The best part is, no matter which tool you select, you can always tweak the temperature of the image by simply sliding the Temperature bar a bit until you are happy with your photo.
No more jaundice photos. Enjoy!