Photoshop Fun: Using Levels to fix image tones
Written by Jamie Chambers
Whether you have an image that is underexposed (too dark) or overexposed (too bright), you can easily correct it by adjusting the overall tone, or variance of light and dark in the image.
Using Levels allows you to independently darken the shadows, brighten the highlights and alter the midtones.
1. Open an image to adjust.
2. Go to Image > Adjustments > Levels or add a Levels Adjustment Layer. You should now see a histogram or graph plotting the brightness of an image from dark (on the left) to bright (on the right). If the histogram is heavily weighted to the left, your image contains a lot of shadows or black (underexposed). If the histogram is weighted to the right side, your image has a lot of highlights or whites (overexposed). Our example is underexposed.
3. Make sure the Preview button is checked and then lighten the midtones of the image by moving the gray point to the left. This will change the histogram and you will immediately see the changes in image. Next, adjust the highlights by moving the white point to the left. Once you are satisfied with the image, click OK.
If your photo is overexposed, start with the midtones (gray point) and move it to the right. Then adjust the black point by moving it to the right.
You must experiment with these points since the amount you move them depends on your particular image.
By the way, it is not incorrect to have a histogram that leans to the right or left, but usually having a balanced overall tone creates a better image.