Level 3

Lesson 14

Learning how to make tonal adjustment and color adjustment using the Levels command

Introduction

The Levels command lets you correct the tonal range and color balance of an image by adjusting the image’s shadows, midtones and highlights individually.

The following lesson will teach you how to correct the photo’s overall contrast by using the Levels command, as well as remove unwanted color cast by using an eyedropper in the Levels dialog box.

In Lesson #13, we have moved the stain from the photo. Now, we will look into the image’s other areas that need correction.

As we can see, this photograph is dull and has a blue color cast.

We will fix this by using the Levels command.

·   Go to the “Menu bar”.

·   Choose Image > Adjustments > Levels.

The “Levels” dialog box displays a histogram of the image, showing us a quick picture of how the pixels are distributed.

The horizontal axis of the histogram represents the color values from darkest (0) at the left end to brightest (255) at the right end; the vertical axis represents the total number of pixels with that value.

There are three triangular sliders below the histogram. The black slider controls the shadows, the gray slider controls the midtones, and the white slider controls the highlights.

·   Check the “Preview” box so that we can see the effect of changes in the image.

The lack of pixel values at the left end of the histogram reflects the lack of contrast in the shadows.

·   Drag the black slider to the edge of the first group of pixels on the left end of the histogram.

As we drag, value in the “Input Levels” first text box changes from 0 to 18.

Upon this adjustment, the image is darkened and the contrast in the shadow areas increases.

The histogram displays a tall spike and some peaks on the right side. This means a great number of pixels are already white. So, we will leave the white slider untouched.

·   Drag the gray slider a short distance toward the right side.

Doing so will darken the image.

To determine how far to drag the gray slider, watch the effect on the image, and make sure that we don’t lose important detail.

·   Stop dragging the gray slider when the image looks good.

This time, value in the “Input Levels” center text box changes from 1.00 to 0.85.

After this adjustment, the medium grays in the image are darkened.

Then, we will remove the color cast from the image.

·   Select the [ Set Gray Point Eyedropper ] tool.

·   Click the area in the image that should be gray.

As a result, the blue color cast is removed.

Notice: Equal values of red, green and blue make a neutral gray.

·   Click [ OK ] to apply the changes.

·   Go to the “Menu bar”.

·   Choose File > Save.

Save our work and then go to the next lesson.

Conclusion

In this lesson, we learned how to use the Levels command to make tonal corrections by adjusting an image’s shadows, midtones and highlights individually.

We also learned that we can remove a color cast by using the gray eyedropper in the Levels dialog box.