Using the eyedropper tools to set the black and white points

You can use the eyedropper tools to set the black or white points in an image. Keep in mind that when the eyedropper tools shift the tonal value of a pixel to the black point (0) or white point (255), the amount of shift in the pixel value is applied to every pixel in the image. So, all pixel values are shifted equally higher or lower, depending on whether you're setting the black point or white point.

This behavior differs from the Input Levels sliders and the Curves (Photoshop) end points, which set the black point in an image while preserving most of the tonality in the highlights and set the white point while preserving most of the tonality in the shadows. Further, both Levels and Curves (Photoshop) make gamma adjustments without affecting either the black or white points. For more information, see Using the Levels dialog box and Using the Curves dialog box (Photoshop).

To set the black and white points using the eyedropper tools:

1. Open the Levels or Curves (Photoshop) dialog box.

By default, the target value for the Set Black Point Eyedropper tool is 0 and the target value for the Set White Point Eyedropper tool is 255.

2. To specify the target value for the black point or white point, double-click the Set Black Point Eyedropper tool or the Set White Point Eyedropper tool. Use the Color Picker to specify the target value.

Depending on the output device for your image, you may want to set a higher black point value or a lower white point value.

3. Select either the Set Black Point Eyedropper tool or the Set White Point Eyedropper tool. Then click in the image where you want to set the black or white point.
4. If necessary, make any further adjustments in the Levels or Curves (Photoshop) dialog box.
5. Click OK.