Setting Highlights & Shadows

In this tutorial you'll learn how to specify two tonal areas of your image: the highlights and the shadows. This technique is crucial for rescuing images that are either too dark or too light and for preparing them for printed output so that the highlight areas are preserved (i.e., don't "blow out") and the shadow areas are maintained (i.e., don't "plug up" with ink).

Although the specifications used in this tutorial are for typical CMYK output, they'll also work well for our online purposes. The instructions are for Photoshop CS4 but the process is very similar for earlier versions of Photoshop.

Many thanks to Michael Ninness from Adobe for these numbers.

As well, you'll learn how to remove a color cast (if any) from the image.

The original image is obviously faded, has a strong overall yellow cast, and no true blacks or whites.

Start by creating a new adjustment layer (Layer > New Adjustment Layer > Levels). Notice that there are no pixels in the image that are 100% black (left side of histogram).

You will now modify the eyedropper settings by double-clicking on the black and white eyedroppers and then by specifying new values appropriate for each.

First, double-click the black eyedropper in the Levels panel. This will open up another dialog box (see below).

In the CMYK section of this dialog box enter the following values then click the OK button: C = 75 / M = 63 / Y = 63 / K = 95

You are presented with a dialog that allows you to save the values you just entered as your new defaults. Click Yes tomake the new setting your default; otherwise, click No.

Now double-click the white eyedropper.

In the CMYK section of this dialog box enter the following values then click the OK button: C = 5 / M = 3 / Y = 3 / K = 0

Once again, you are presented with a dialog that allows you to save the values you just entered as your new defaults. Click Yes tomake the new setting your default; otherwise, click No.

These settings are really designed for print work and are intended to maintain the printed dot structure for both highlights and shadows but they'll also work for us to ensure that the image highlights and shadows still contain some level of detail.

Now with the white eyedropper selected click on the lightest part of the image that still has some detail in it (i.e., don't click on a specular highlight).

Now select the black eyedropper and click on the darkest part of the image that still has some detail in it.

Next, select the gray eyedropper and click the image in a midtone area that should be neutral in color. If your image doesn't have any such areas you'll need to use another method to reduce color cast.

Finally, use the gamma slider in the Levels dialog box to lighten (or darken) the midtones of the image. I this example, the midtones levels have been slightly lightened but the newly established shadow and highlights are maintained.

When you're satisfied with your results click OK.

Before.

After. The corrected image.

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Setting Hilights & Shadows