When you take a picture with your digital camera, the camera image sensor distributes the red, green, and blue pixels according to their brightness. An 8-bit image has 256 levels. Dark pixels are at the low end of the scale, while the brightest pixels are at the high end of the scale. In certain conditions, a digital camera may not distribute the pixels properly, and your image may be lacking pixels at the low end of the scale. If this happens, the shadow areas of your image are not well defined. If your image is lacking pixels at the high end of the scale, highlight areas will not be well defined. You can correct for any deficiencies in levels by applying the Auto Levels command. However, when you correct levels, you may notice that the image acquires a color cast. For example, after applying the Auto Levels command, the image may look bluish or reddish. You can correct this deficiency with the Auto Color or Color Cast commands. The following image is in need of color correction:
APPLY THE AUTO LEVELS COMMAND
To correct an image that is lacking contrast, or appears washed out, choose Enhance | Auto Levels. After invoking the command, Photoshop Elements examines the distribution of pixels and then redistributes them as needed to correct for any deficiencies. The following image shows the image from above after the Auto Levels command was applied. Due to the size of this illustration, you may not be able to see a color cast, and you may not notice a color cast when you preview your own images after applying the Auto Levels command. However, it's always a good idea to use the Auto Levels and Auto Color commands in succession. After you apply the command, you may still not notice a difference.
ADJUST IMAGE COLOR
You can also manually adjust the color of an image. Photoshop Elements has several commands for adjusting color, including the Color Variations command, which makes it possible for you to adjust color with several visual references.
- Open the image that needs color adjustment.
Choose Enhance | Adjust Color | Color Variations to open the Color Variations dialog box. The following image shows a picture with a couple of variations adjustments applied. The left window shows the image before, and the right window shows a preview with adjustments applied.
- Select the color range you want to adjust.
- Drag the Amount slider to determine how much color adjustment is applied. If you only need subtle color adjustments, drag the slider toward the left. If you need to apply larger amounts of color adjustment, drag the slider toward the right.
- Click one of the thumbnails to have the adjusted image match the variation. After you apply a variation, the thumbnails are adjusted accordingly. If desired, you can apply additional color variations to further change the image.
- Click the Lighten or Darken variation to lighten or darken the tonal range you are adjusting.
Click the Saturation radio button if the saturation of the colors in your image needs to be adjusted, and then click the Less Saturation or More Saturation variation, as shown next.
After the image is adjusted as desired, click OK to apply the variations to your image.
If the color cast isn't corrected by clicking the spot you thought would solve the problem, click another area in the image. Click as often as needed until the image looks good to you.
- http://tech.yahoo.com/gd/color-correcting-digital-photos-in-adobe-photoshop-elements/191745;_ylt=AlMrsN2Dl1wjkHA9dMiyFzAvLZA5
