Adjusting color and tone
To improve image quality, you can adjust an image’s color and tone to correct color casts, balance excessive darkness or lightness, or alter specific colors.
In this section, you’ll learn about
• adjusting color and tone quickly in the Image Adjustment Lab
• adjusting image color and tone
• working with color channels
Adjusting color and tone quickly in the Image Adjustment Lab
The Image Adjustment Lab lets you correct the color and tone of most photos quickly and easily.
The Image Adjustment Lab consists of automatic and manual controls, which are organized in a logical order for image correction. By starting in the top right corner and working your way down, you can select only the controls you need to correct the problems specific to your image. It is best to crop or retouch any areas of the image before beginning the color and tone corrections. For information about cropping and retouching images, see “Cropping images” on page 281 and “Retouching” on page 315.
As you work in the Image Adjustment Lab, you can take advantage of the following features:
• Create snapshot — You can capture the corrected version of an image in a “snapshot” at any time. Thumbnails of the snapshots appear in a window below the image. Snapshots make it easy to compare different corrected versions of the image so you can choose the best one.
• Undo, Redo, and Reset to original — Image correction can be a trial and error process, so the ability to undo and redo corrections is important. The Reset to original command lets you clear all corrections so that you can start again.
Using automatic controls
You can begin by using the automatic correction controls:
• Auto adjust — automatically corrects the contrast and color in an image by detecting the lightest and darkest areas and adjusting the tonal range for each color channel. In some cases, this control may be all you need to improve an image. In other cases, you can undo the changes and proceed with more precise controls.
• Select white point tool — automatically adjusts the contrast in an image according to the white point that you set. For example, you can brighten an image that is too dark by using the Select white point tool.
• Select black point tool — automatically adjusts the contrast in an image according to the black point that you set. For example, you can darken an image that is too light by using the Select black point tool.
Using color correction controls
After using the automatic controls, you can correct color casts in your image. Color casts are typically caused by the lighting conditions when a photo is taken, and they can be influenced by the processor in your digital camera or scanner.
• Temperature slider — lets you correct color casts by “warming” or “cooling” the color in an image to compensate for the lighting conditions at the time the photo was taken. For example, to correct a yellow color cast caused by taking a photo indoors in dim incandescent lighting, you can move the slider toward the blue end
to increase the temperature values (based on degrees Kelvin). Lower values correspond to low lighting conditions, such as candlelight or light from an incandescent light bulb; these conditions cause an orange cast. Higher values correspond to intense lighting conditions, such as sunlight; these conditions cause a blue cast.
• Tint slider — lets you correct color casts by adjusting the green or magenta in an image. You can add green by moving the slider to the right; you can add magenta by moving the slider to the left. Moving the Tint slider after using the Temperature slider lets you fine-tune an image.
• Saturation slider — lets you adjust the vividness of colors. For example, by moving the slider to the right, you can increase the vividness of a blue sky in an image. By moving the slider to the left, you can reduce the vividness of colors. You can create a black-and-white photo effect by moving the slider all the way to the left, so that all color in the image is removed.
Correction of a color cast depends on the type of light that caused the cast. The image on the left was taken indoors in incandescent light. The image on the right is the corrected version.