Creating Depth, Part 3: Light, Color and More on Deep Staging
The third part of the Creating Depth series is mostly about light and color, and how they impact depth perception. There is also a section on camera and subject placement and how to maximize available space as a mean to increase image depth.
Deep staging for cinematographers
Directing action so that it creates movement on the depth axis mostly falls in the domain of the director. But the cinematographer also has some staging tricks to promote depth. It is probably obvious, but let’s put it out explicitly: one main reason small movies look small is that they are shot in small spaces. It is really that simple. Shoot in a small room, and you’ve got a cramped and confined scene. Shoot in a hangar, and suddenly there is space and air to the shot. A larger space will naturally create a deeper frame. It is no coincidence that a typical big production stage is spacious and the sets are often larger than life. Shooting in a large space is really the simplest way to have depth in the image.
Unfortunately, the large set is often a luxury in the low budget world. But there are tricks that help photograph a deeper space. All of the following are based on a single underlying principle: select a viewpoint so that a (seemingly) great range of depth is put on display.
- Pull the subject away from walls. This is a simple and effective technique to increase the depth of the scene, even more so when shooting squarely against the wall. By pulling the subject (and the camera, to preserve subject size) you are effectively pushing the background farther back. This also opens the opportunity to place well-differentiated props between the subject and the background walls: this heightens the sense of depth by creating more depth planes. And this trick has bonus benefits: less distracting shadows on the walls; free space for back lights, if needed; and space for running cables, positioning stands, etc.
- Shoot against a corner. For any subject positioned in a space with a rectangular floor plan the longest distance between the subject and a point at the walls is towards a corner. So take advantage of this and include a corner of the room in the frame. This gives the deepest frame possible. Having the corner in the frame will also create natural diagonals, especially with close-to-subject viewpoints and wider lenses, resulting in a more dynamic composition.
Have the subject deeper in the frame, behind a well defined foreground. The foreground may frame the subject, or simply serve to enhance the sense of depth in the image. One special case of this principle is the over-the-shoulder shot which is a classic coverage device, and can be seen in pretty much all movies: some defocusing of the foreground character (with their back to the audience) creates an unobtrusive foreground plane. Another special case: have foreground elements or props create leading lines into the frame. Leading lines are a compositional device for guiding the eye and increasing subject importance, but they can also assist depth perception when oriented along the depth axis.
- Show the space outside the room in the frame. In its easiest incarnation that means including open interior doors in the frame. This adds the space of the adjacent room to the scene and effectively deepens the shot. It also creates a natural exit point for the eye in the frame. A bit harder (but possibly more rewarding) is including the exterior in an interior image. Either through windows, or through open exterior doors. The difficulty lies in matching light levels: this may require raising interior light levels or gelling windows with ND sheets to prevent blowing the exterior to white. There is also the danger of strongly disbalancing the composition when letting overly busy exteriors in.
Light and depth
Light is the main weapon of the cinematographer. It has a multitude of functions: creating illumination for proper exposure, manipulating mood, modeling character and texture, conveying time of day and time of the year, focusing attention, tweaking composition, etc. But here we are interested in its power to differentiate planes. Lighting separate areas of the frame in distinct tones is a major tool for space differentiation. And space differentiation is a prerequisite for perceiving distinct depth planes. It is a basic principle: if two areas look different, they are easily accepted as separate. This is somewhat related to light as a modeling tool: lighting different planes of an object to different tones separates the object’s features and reveals form.
The most popular way to achieve this is alternating light and dark planes in the frame along the depth axis. The juxtaposition of shadow and light is a very effective approach for space structuring because areas are cleanly separated, and this helps the mind to map the spatial relationships within the scene.
Seemingly chaotic splashes of light in a dark environment can be as much effective and compositionally interesting. Light and shadow can be loosely interspersed. A particular depth plane can have both light and shadow. It is desirable to alternate them along the depth axis, and not necessarily keep a similar light level across the plane.
This also applies to subject separation. As described previously, delineating subjects is beneficial for depth perception because it helps the brain to judge interposition and occlusion. There are a couple of ways to aid delineation through lighting. First, through contrasting subject tones with background and foreground (where applicable) tones. This is essentially the above method of contrasting light: subject and background are positioned and lit so that bright elements of the figure fall against a darker background, and dark parts fall against a brighter background. This effectively models subject outlines.
The second method is used with dark subjects on dark backgrounds. It involves backlights or rimlights to rim the subject and separate it from the background. In general, any light aimed at the subject and positioned at an angle greater than 90 degrees with respect to the camera-subject axis will produce some sort of an outlining effect.
Both pools of light and lines formed by practical lights themselves are prime candidates for exploiting diminishing perspective and the principle of relative size. This is a popular way to create interest and accentuate depth in hallways or any possibly bland but deep space.
Hard light is also a natural source of leading lines. It creates both shafts of light (through a bit of smoke) and striking shadows. Both light shafts and long shadows (especially from a relatively low backlight) can be used to lead the eye deeper into the frame.
A few words on color and depth
Color can be used in a similar way for the purpose of depth enhancement. In fact, in the dawn of color film some cinematographers thought that color alone is enough for separation and differentiation, and didn’t hesitate to light the whole scene flat. This is a bit optimistic: after all, the eye is more sensitive to brightness variations than changes of color. Nevertheless, color plays an important role. It is no coincidence that some color grading schemes are popular (looking at you, blockbuster teal). Warm skin tones pop more against a cold background (also see color perspective in the previous article of the series). That’s one reason why blue is often production design favorite color for props and walls.
One way to infuse a cold tint is shooting with cold light while keeping the white balance at a warmer color temperature. This is sometimes achieved by exposing tungsten balanced film stocks to daylight or near-daylight balanced light without on-lens correction or with partial lens filter correction. This will throw greys towards blue, and when done with good measure skin will be desaturated but not overcooled, especially when paired with some warmer fill. Opposing light colors create color separation, which is a good base for additional DI color work, with or without bringing white balancing back in post. The same approach is, of course, valid for digital cameras through creative white balancing.