You can make color and tonal adjustments in the Color Variations dialog box by comparing and choosing different thumbnail variations of the photo. Color Variations works best for average tone images that don’t require precise color adjustments.
Note:
You can’t use the Color Variations command with images in Indexed Color mode.
A color cast is an unpleasant color shift in a photo. For example, a photo taken indoors without a camera flash may have too much yellow. The Remove Color Cast command changes the overall mixture of colors to remove color casts from an image.
Original (left), and after removing the green color cast (right)
You can use the gray color picker in the Levels dialog box to quickly remove a color cast. Double-click the color picker and make sure that the RGB values are equal. After you close the Color Picker, click an area in your image that should be a neutral gray.
The Adjust Color Curves command improves color tones in a photo by adjusting highlights, midtones, and shadows in each color channel. For example, this command can fix photos with silhouetted images resulting from strong backlighting, or slightly washed-out objects that were too close to the camera’s flash.
In the Adjust Color Curves dialog box, you can compare and choose different tonal presets. Select from the list of styles in the Select A Style box. To fine-tune the adjustment, adjust the highlights, midtone brightness and contrast, and shadows.
Adjusting color curves in an image
A. Select a Style (choose from presets) B. Adjust Sliders (custom options)

