Add Background Lighting To Achieve Three-Dimensional Space

Lighting the background of your shot can add depth to a scene and up the production value of your project. Here’s everything you need to know about the technique.

The primary focus of lighting is to expose your talent in a manner that correctly accentuates the tone of the story, as well as maintaining the practical principles of a composition — exposure, shadow detail, highlight detail and so forth. A secondary, and often overlooked area, is background lighting.

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Background lighting is the act of illuminating the area behind the actors, which is often out of focus and perhaps even obstructed by the talent themselves. The first question: Why even bother to light the background if it’s going to be out of focus and possibly only partially viewable? The principal reason is that background lighting helps creates three-dimensional space within a two-dimensional plane.

Ok. What do I mean by that?

In real life, everything has a dimension — height, width, depth. We can answer questions relating to visual properties from having this information. How tall is that building. How far is that man? The core principle of any screen is that it is two-dimensional. Cinema screens, television sets, mobile phones, and computer screens are flat surfaces. The visual information from those screens cannot be measured, especially, and most importantly, the depth.

Naturally, an audience member should be able to watch the film or TV and accept that what is being shown is an actual representation of the three-dimensional characteristics of those objects. It is a filmmaker’s duty to portray this correctly. On the flipside of that, a filmmaker can also use it to his or her advantage by manipulating what the audience perceives as an actual three-dimensional representation.

A primary example would be forced perspective, a technique that was used in The Lord of the Rings to make Ian McKellen’s Gandolf seemingly tower over his Hobbit friends.
The term to describe the on-screen depth is called deep space. Sometimes it’s referred to as deep staging. This is the illusion of a three-dimensional space on a two-dimensional surface. This is achieved using a number of depth cues:
• Perspective

• Size Difference
• Object Movement
• Camera Movement
• Camera Focus
• Tonal Separation
• Color Separation

The key features we will look at are tonal separation and color separation, because this is chiefly achieved with lighting. Background lighting serves to add interest, not attention; as soon as the background feature becomes more important than your talent, you’ve failed.

Background lighting can also act as a function to separate your actor from the darkness of a dark set. In this shot below, I was attempting to mimic the cinematography found in NBC’s gone-too-soon Hannibal.

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My shot is on the left. As you can see, I had not correctly set the lighting up to fully separate the actress from the dark environment. As a result, the actress merges into the darkness of the set. (Although, ironically, that helped with the story symbolism.)

However, technically I had not correctly lit the background.

Before we continue, it’s important to distinguish the difference between backlighting and background lighting. A backlight hits an actor or object from behind and is usually placed higher than the object it is lighting. A backlight is often used to separate an object or an actor from a dark background, and to give the subject more shape and depth. Backlighting can help bring your subject out and away from looking two dimensional.

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That lamp in the shot  helps to break Hannibal away from the background.

Four Techniques for Great Background Lighting

There are a few ways to go about lighting your scene’s background. Here are four that work every time.

1. Color (Temperature) Separation

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If you don’t have a full lighting kit at hand, this could be your cheapest and easiest method to break your actors away from flat space and further your production value. If your actor is being exposed with tungsten lighting, you can use sunlight or converted tungsten light to illuminate the background. Of course, it can also be the other way around. Take the shot above from Terrence Malick’s The Tree of Life.

Brad Pitt’s character is being exposed by a household lamp, which the camera has been calibrated for, and the background has been lit with natural sunlight. It separates the talent from the background and forms natural depth to the scene. Using complementary colors will always add a nice aesthetic to the scene.

2. Practical Lighting

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I have to apologize for the following tip. If you haven’t noticed this already, it’s going to ruin a lot of films (like A Serious Man, seen above) and TV shows for you. Household lamps are perfect for adding pools of light across the background of your set. It can bring your actors away from their environment and stop the composition from becoming flat. Here’s the part which you might hate me for: Almost all practical lights used in the background serve no actual purpose to the scene or characters. In fact, in most circumstances, there’s enough light for there not to be a lamp on. However, in practicality, they do a good job of adding texture (and interest) to the background.

3. Sunlight Slash

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In the book Set Lighting Technician’s Handbook – Film Lighting Equipment, Practice, and Electrical Distribution, author Harry C. Box says:

Light tends to build up on backgrounds and can start to flatten everything out. The gaffer looks for ways to break up the background or create variation, gradation, or particular highlights. If a scene takes place in a set with lots of windows, it is natural to scrape a slash of sunlight across the far wall, and across the furnishings. Large Fresnels or PARs are commonly placed outside of windows for this purpose.

A single streak of light is one of the most efficient ways to break up the foreground from the background. Filmmaking company Stillmotion used this technique in a book trailer for author Stephanie Henry.

Fortunately for us, they also made a blog to accompany the video, and they provide stills of the light streak and how it was created. It’s worth reading the entire blog, as
Patrick Moreau breaks down a lot of lighting tips. As you can imagine, the scene below would fall pretty flat without that streak going across the background.

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A sun streak can be achieved by using a set of flags, and it’s widely recommended to use a Fresnel lamp because of their small surface area (that will create a harder light, great for shadows). If you’re not in possession of flags, look around at your location and see what on-set obstacles you can find to cut the light. I once achieved this effect by placing the Fresnel behind a door that was ajar.

4. Shadows

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Alternatively, instead of just a solid streak of light, you can employ the use of shadows to your composition. A favorite and classic of cinema in itself are the use of blinds or window frames. With many Fresnels, you can place a gobo to project a pattern onto the wall. If you don’t have a gobo, you can use actual objects like plants or trees. It’s hard because we don’t have the before shot, but I can tell you that the still above (from Akeelah and the Bee) wouldn’t be the same without the background light and shadow.

Bonus Consideration: Flat Space

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It’s worth mentioning that sometimes flat space is exactly what you want to achieve. Flat space emphasizes the two-dimensional aspect and can work toward your goal of highlighting a particular symbolic meaning.

Take the still above from Garden State. Zach Braff’s character is very much having an identity crisis in the film and doesn’t know where he belongs in the world. The flat cinematography (along with the matching shirt) puts him in a position of almost being invisible. This would not have had the same symbolic meaning if any of the depth cues — perspective, size difference, object movement, camera movement, camera focus, tonal separation or color separation — were present.