Figure 1. Mouse over, or click, to
see the original dark and light gray chips
The Eyedroppers are used to set the black, mid and/or white points of the
tonal scale to specific areas in the image. This, in effect, stretches the
tonal range of the image to the full 0 - 255 range.
In the example in Figure 1, the black eyedropper
was clicked on the dark gray chip on the left and the white eyedropper
was clicked on the light gray chip on the right. By using the black
eyedropper and clicking on the dark gray, we are telling Adobe Photoshop this
tone and anything darker is now black. By using the white eyedropper and
clicking on the light gray chip, we are telling Photoshop this tone and anything
lighter is now white. Mouse over the After label in Figure 1 to see the
The eyedroppers are a good way to set black, mid and/or white points when we
want to use specific areas in the image instead of the Levels histogram.
In addition, they can be used to help neutralize a
color cast in an image. Correcting color casts using Levels is
discussed on the
Levels Color Correction page.