An image with very little midtone tonality is considered to have a lot of contrast, whereas an image with considerable midtone tonality is considered to have minimal contrast. Often, an image with too much midtone tonality looks flat. Adding contrast to the image can add depth to it. However, you add contrast to the image at the expense of detail in the midtones, so a little contrast goes a long way.

1. Select a photo.

2. In the Enhance area of the Adjustments inspector or the Adjustments pane of the Inspector HUD, use the Contrast parameter controls to modify the contrast between light and dark colors in the photo.

   

   A value below 0.0 decreases the contrast in the image. A value greater than 0.0 increases the contrast.

The Definition parameter is useful for adding local contrast (adding contrast only to the areas of the image that need a contrast adjustment) as well as reducing haze.

1. Select a photo.

2. In the Enhance area of the Adjustments inspector or the Adjustments pane of the Inspector HUD, use the Definition parameter controls to add clarity and definition to the image.

   

   A value greater than 0.0 increases the clarity in the image.

Increasing the saturation of an image can make the colors appear more pure, and many people like the effect of an image whose colors are more saturated than they would appear naturally. However, you can easily oversaturate an image. In the process of making the colors more pure, subtleties in shades of colors disappear, often resulting in reduced detail in the image. To ensure that visual elements aren’t unnecessarily lost, pay attention to the details in your image as you increase saturation.

1. Select a photo.

2. In the Enhance area of the Adjustments inspector or the Adjustments pane of the Inspector HUD, use the Saturation parameter controls to add a burst of color to an image, or remove color from an image.

   

   A value below 1.0 decreases the color saturation in the image, and a value above 1.0 increases the saturation. A value of 0.0 removes all color from the image, making it grayscale. A value of 4.0 increases the saturation by 400 percent.

The Vibrancy parameter applies saturation to the image in a nonlinear manner. Colors that are already saturated are left alone, while saturation is added to all other colors. In addition, the Vibrancy parameter takes skin tones into account, leaving them untouched. This allows you to take a portrait and desaturate the image except for the skin tones.

1. Select a photo.

2. In the Enhance area of the Adjustments inspector or the Adjustments pane of the Inspector HUD, use the Vibrancy parameter controls to adjust saturation in the image without affecting skin tones.

   

   A value below 0.0 decreases the color saturation in the image, and a value above 0.0 increases the saturation of the nonsaturated colors. A value of –1.0 removes all color from the image, making it grayscale except for any skin tones.