Mastering Lighting: Ambient Occlusion

Have you ever heard of the term ambient occlusion before?

It might be an unfamiliar term to you now, but by the end of today, you’ll not only know what it means but also understand the crucial role it plays in lighting! We’ll break it down using both outdoor and indoor examples so it’s real easy to grasp. Let’s dive in and tackle this new word together right away!

What is Ambient Occlusion? 

In a recent email, we went over the term, “ambient lighting”–which is the light that appears in shadow. Ambient occlusion, is a term used to describe the darkest part of a shadow where light has the hardest time reaching!

Let’s take a look at the shadow inside of the bag in our image above. Notice how this shadow gets darker the deeper we get. This is because the deeper we go into the bag, the tighter the space is. And the tighter the space, the less light is able to enter.

Underneath the creature’s foot (the one touching the bag) is another example of tight space. The shadow is much smaller so you might not see it at first but look real close! There is a darker shadow in the tight space where the foot comes in contact with the bag.

Ambient Occlusion is Where Light Cannot Reach

Ambient occlusion exists because light enters our shadows and brightens the areas most open to the environment. In our example above, the string of lights creates a nice light source, illuminating the room and the subjects in the scene. This light source bounces off walls and other objects, allowing it to brighten our shadows. However, even bounce light has a tough time reaching tight spaces. The areas where light struggles to reach the most are where our ambient occlusion is located!

Ambient Occlusion in Portraits

In our portrait example above, we see many different levels of brightness within the shadows. There is a gradient of shadow on her face, under her chin and neck, in her hair, and even on her clothing. These shadows are all created by the sun—wherever the sun cannot reach is shadow!

However, we are outdoors in a bright scene where the sky is also emitting light. The sky acts as a large diffuse light, reaching into areas of shadow that the sun can’t illuminate, brightening them, and lightly tinting them a beautiful blue. Where the sky’s light cannot sneak into is where ambient occlusion occurs. For example, there is a dark shadow right under the chin, on her right shoulder (near her hair), and where her shirt meets her skin!

If you wish to learn more about lighting, access our FREE lessons on shadow theory, in Maria Lia Malandrino’s course, “Lighting + Shading: Make your Art Shine!”