Understanding Levels

The Levels tool corrects tonal ranges and color balance issues. With Levels, you can fix poor exposure and perform color correction by manually identifying a white point and a black point in the image. Nearly every image can benefit from making a Levels adjustment.

To understand Levels, it is essential to be able to read a histogram. The Levels tool has its own histogram that works as a visual guide for adjusting the image. A Histogram is a graphical representation of the tonal values of your image. It illustrates how the pixels in a photo are distributed across brightness levels ranging from black (0% brightness) to white (100% brightness). Histograms are a useful way to judge the exposure and contrast of a photo and are widely used by advanced amateur and professional photographers.

Histograms are read left to right. The left edge depicts pure black. As you progress to the right you move through the shadows, mid-tones, and highlights. The right edge depicts pure white. As you move the sliders for Exposure, Shadows, Highlights, Blacks, and Whites in the Tone adjustments, you’ll notice that the Histogram adjusts as tones are changed.

In addition to representing Luminance values, a Histogram also depicts Red, Green, and Blue color channels. By default, the luminance and color values are shown together in the RGB view. However, you can view each channel separately by clicking on the Histogram and choosing between RGB, Red, Green, Blue, and Luminance. These different views help spot color balance and other issues.

Fixing Exposure and Contrast with Levels

In this example, we’re using a stunning backlit photo of a lion. However, due to the way the subject is lit, the image feels flat and lacks contrast. We’ll use the Luminance channel in Levels to correct the tone and contrast issues.

1. Open an image in Single Photo View, then open the Edit Panel in the right panel.

2. Locate the Levels section, and if necessary open the section by clicking on the disclosure arrow next to Levels.

3. Click or tap on the L (luminance) button.

4. Move the white point slider slowly to the left. This affects the image’s white point and allows you to reassign where white should begin in the image.

*TIP: It can be helpful to turn on clipping warnings when working with Levels. They provide a visual indicator that shows if detail is being lost in the brightest or darkest areas of an image. Toggle clipping warnings ON and OFF using the J keyboard shortcut.

5. Move the black point slider slowly to the right. The more you move the slider to the right, the more contrast is introduced into the image.

6. Move the midtones slider. Moving the slider to the left will add more light, and moving it to the left will subtract light.

Correcting Color Balance with Auto Levels

When working with the Levels tool, you may have noticed the Auto button. Auto Levels analyzes the histogram data and uses that information to modify the individual R (red), G (green), and B (blue) channels. In many cases, Auto will correct or markedly improve color balance and exposure issues.

In this example, we’ll use a photograph of a young Cheetah. The original has a mild green colorcast and is slightly underexposed.

1. Open an image in Single Photo View, then open the Edit Panel in the right panel*.

2. Locate the Levels section, and if necessary open the section by clicking on the disclosure arrow next to Levels.

3. Click or tap on the Auto button to automatically adjust color.

4. Move the midtones slider to refine the Auto adjustment to taste.. Moving the slider to the left will add more light, and moving it to the left will subtract light.

Removing Color Casts with Precision

In the first example, we made a Levels adjustment to all channels evenly. In the second example, we let Mylio Photos make an automatic adjustment to each channel using the Auto button. The Levels tool also allows you to view and adjust each color channel independently. This allows us to correct color cast issues, incorrect white balance, or photos captured with mixed or colored lighting. In this example, we’ll use the eye dropper tools, and work with each individual color channel to obtain perfect color on an image with a trio of young wild cats.

1. Open an image in Single Photo View, then open the Edit Panel in the right panel*.

2. Locate the Levels section, and if necessary open the section by clicking on the disclosure arrow next to Levels.

3. Click or tap on the black point eyedropper, move your mouse over the photo, locate an area that should be pure black, and click or tap to set a sample point. For this image, I chose an area near the cat’s eye.

4. Click or tap on the white point eyedropper, move your mouse over the photo, locate an area that should be pure white, and click or tap to set a sample point. In this photo, I chose an area with a very bright highlight on a blade of grass on the right side of the image.

5. Click or tap on the gray point eyedropper, move your mouse over the photo, locate an area that should be a neutral gray, and click or tap to set a sample point. For this image, I chose an area on the cat’s chest. When you’re finished with the eyedropper tools, click or tap Done at the bottom of the screen.

*TIP: Not all images will have an area that is pure white or pure black. Only use an eyedropper tool on areas where pure white or pure black is available to sample.

6. If necessary, select the R (red), G (green), and B (blue) channels. Use the blacks, midtones, and whites sliders below each color channel to adjust the result to your taste.