In this article I wrote about classical key light placement and classical portraiture to illustrate how artists and cinematographers have traditionally gone about lighting faces. Fill light is often derided as the light that simply opens up the shadows, but it can do much more than that. It can have a shape and beauty all its own, and it can save you when your key light placement is not optimal.

The fill light can be the most important light that you place on a set, and there are a lot of choices to be made when selecting a strategy. Fill lights can be hard, soft, very soft, or soft to the point of being invisible. They can be placed on the opposite of the camera from the key or on the same side, above or below the lens, behind the camera or in front of it. Conrad Hall, ASC spoke on occasion about creating “room tone,” or defining the ambience of a location with one carefully placed bounced or diffused source. This article won’t go to that kind of detail but I do want to show you the power that the fill light has over a human face.

Just for fun I thought I’d put our virtual stand-in right up against a wall, which is one of the worst scenarios for lighting. My experience is that poorly placed fill shadows will give away that a scene is “lit” long before anything else will. When I’m stuck lighting people against walls or shooting in rooms with white walls I pay a lot of attention to the quality and number of shadows as they tend to become very prominent.

Here’s the classic “key + fill” scenario:

The key has been slightly softened, probably by the equivalent of a 2’x3′ frame of Lee 250 in front of a light that’s about 6′ away from the subject. The fill shadow has about the same hardness to it. This is the “45-degree-off-lens-axis-and-tilted-45-degrees-down” formula that every film school teaches. This probably stems from the good old days of big studio features where all the lights were hung from an overhead grid. From this angle the key works well on many faces (with a little tweaking: perhaps more frontal for women and more from the side for men) and the fill does a fair job of filling in the shadows.

There are some drawbacks to this strategy. There are a lot of situations where the additional fill shadow says “lit” to me. In nature it’s rare to have a hard fill shadow that’s opposite the main light shadow, and unless the fill is at least a little bit hidden by increasing the size of the source and softening the shadow it can be a bit of a lighting giveaway. Still, there’s an awful lot of projects that are lit with some variation of this lighting setup. I see it a lot in episodic television: when I look into an actor’s eyes I can see two sources, one on either side of the camera. It can look quite good if done correctly.

For me “correctly” means the fill source is very large and very soft, so that the shadows it casts on walls and furniture have indistinct edges and are very delicate, and not distracting. There are limited times when a fill source can be hard; the most obvious is if I’m filling someone that is quite far away from the camera and the hard shadow isn’t obvious due to diminished perspective or soft focus.

The key drawback of this key+fill setup is that there are only two tones on the face: the brighter tone on the key side and the darker tone on the fill side. A soft key creates greater tonal distribution across the face but a fill light placed at this angle will only contribute one tone on the shadow side.

Some faces have jawlines that cause both the key and the fill lights to merge into one dark shadow beneath the chin. This can also be a bit of a lighting giveaway. One distinct shadow is generally more pleasing. There are exceptions to this, though, and we’ll get to one of those later on.

Occasionally this lighting setup will leave dark spots in the crevices around an actor’s eyes, particularly where the corner of the eye meets the bridge of the nose. This is particularly obvious on the key side, because the brightness of the key makes adjacent shadows look darker than they should.

For the next setup we’re going to bring the fill light in line with the lens height, but still 45 degrees opposite the key:

This setup works a bit better for digging into eye sockets and eliminating double shadows under chins. The fill light is still offset 45 degrees from the lens axis so it’s not getting into all the corners that it could. For example, in this image it is illuminating the corner where the camera right eye meets the bridge of the nose but this is the exception to the rule. Fill lights that are offset from the camera will often not reach into this crevice, and the result is that the darkest part of the face–where neither the key nor fill light reach–is juxtaposed against the brightest part of the face–the key side–which makes it appear darker.

Not good.

This next image shows what happens if we soften the fill light considerably:

The previous image showed what would happen if we used a light through a 2’x3′ frame of Lee 250 6′ from the subject. This shows what happens if we make that source a 6’x6′ frame of grid cloth, which is much denser than Lee 250. By making the source bigger, and by eliminating the beam of the light and making the dense diffusion do all the work (the glowing diffusion becomes the sole light source), we can make the shadow very soft indeed.

Let’s move the light lower:

This shows the fill light still offset 45-degrees from the camera but placed low and tilted up at 45 degrees instead of high and tilted down. I don’t see this very much anymore. This technique is seen most often in black-and-white movies made in the 1940s, back in the days when stars had to look good at any cost and shadows be damned. I wondered for far too long why this position was so popular at that time and eventually realized it was simply opposite in angle to the key light. One was high and pointing down, the other was low and pointing up from the opposite side of the camera.

In old movies this fill shadow is very hard, much harder than I show here, although it is faint because it is not the only fill light. In those movies the set has an overall fill light, and this additional light is meant only for the actor. It’s left as a hard source because it doubles as an eye light, and eye lights pop more if they are hard points of light, or specular highlights.

A specular highlight emits all the light energy from one point, the filament, so that one point is very bright. A soft source may emit the same amount of energy but over a wider area, so while the light coming from the soft source may be the same in total every part of the diffusion or bounce card is radiating less light. A big source means a bigger highlight in the eye, but one that’s dimmer overall because the light energy is so spread out over the source’s surface.

Here’s what happens if we diffuse the fill light further:

As a regular fill position I think this is too obvious for modern use because, while the fill is very soft, any hand gestures near the face will cause an obvious shadow from both the key and the fill as well as a wall shadow that’s 180 degrees off from the key. Shadows that fall directly opposite each other often look fake.

In film school we’re taught that lighting from under the lens denotes horror, but that’s if the light is hard and looking almost straight up at a face. Light from below the lens can be quite beautiful.

For example:

Here the fill light is directly below the lens. I show an example of this technique in this article. Very soft fill light from below the lens can be gorgeous. When I was a camera assistant I worked with a DP who both keyed and filled with bounce light off 4’x8′ sheets of foam core placed under the lens. The light had a very soft, natural feel, as if sunlight through a window reflected off the floor onto the actor’s face.

There’s a great example of soft light from below in the film Driving Miss Daisy. There are several sequences where the camera just wanders through Miss Daisy’s house, and all the rooms on one side of the hallway are lit with soft, warm, upward shadows while the other side was lit with soft blue sidelight. I realized that the motivation for the lighting was warm sun striking the floor through windows on the south side of the house and blue skylight coming through windows on the north side of the house.

Let’s talk more about high-angle lights on the next page…

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There are only two lights that naturally come from the sky: sunlight and moonlight. Every other high-angle light source is artificial. There are an awful lot of artificial sources that are above eye level, but even more that are at or below eye level (table lamps, candles, etc.). There’s always some sort of ambience from the flat thing that the actors are standing on, typically the floor or ground. Soft light from below is one of those things that’s all around us that we never notice until it’s gone. Stand in a room with a black or dark floor and overhead lighting and you’ll notice very quickly that something is missing.

The same thing happens in sets where there’s no ceiling: there’s no ambient light reflected from the ceiling on hair, clothes and walls, and we can detect that something is wrong. That’s why it’s normal for us to put some sort of white material over sets with no ceilings–typically a 4’x8′ piece of foam core or two tossed on top of the grid–to recreate the ambience that results from a white ceiling in a normal room.

Soft light from below can result in upward shadows, particularly hands on faces, but if you’re shooting in a sunlit room that’s probably fine. In fact, it probably looks better than fine because you’re recreating what really happens in a sunlit room. It feels very natural, and almost nobody will be able to tell you why it works because very few people consciously notice the ambient soft light that permeates our world. They will, however, notice if it’s gone.

Light from below the lens creates great eye lights because the slope of the cheek is much less than the slope of the brow. A light from above may be blocked by the brow and never reach into dark eye sockets, but there’s not much to block a light from below. Eye lights are usually distinct from fill lights as they tend to be harder point sources that create a very distinct glint in the eye. An old eye light trick involved removing the lens from an Inky (150w fresnel light) and putting a lot of scrims in front of it, so the Inky became a bright point source that didn’t cast much light into the scene but reflected wonderfully in eyes. These lights were often placed either to one side of the lens or directly below the matte box.

This might be the time to mention that I generally fill from as close to the lens as possible. Fill light near the lens axis has a wonderful smoothing quality because it casts very tiny shadows. Skin imperfections become quite noticeable when lit from the side, but fill light from the lens eliminates or reduces these shadows and helps them to disappear.

Because light from near the lens axis casts smaller shadows it’s possible to get away with a physically smaller fill light closer to the lens when you can’t get away with a larger soft light farther away from the lens axis. Lights closer to the lens axis appear softer than they really are, because the shadows they cast are smaller from the lens’s perspective: most of the shadow is cast behind the object, away from the camera.

Here’s soft light from over the lens:

This is a great position when filling large spaces. It’s not unusual for me to fill a large room by putting a 4’x8′ piece of foam core behind and over the camera and up against a wall. Fill light from below is very pretty but that much upward-facing light isn’t appropriate for all circumstances, such as night interiors. Also, fill light from a distance behind the camera won’t cause actors to brighten considerably if they approach the camera, which would happen if the fill source was directly beneath the lens.

Notice that the fill light doesn’t have much of an impact in our virtual model’s eyes. The only time that might be a real concern is if there’s no key light reflection in them and you’re looking for an extra kick to make them come alive, in which case you could add an eye light.

There is one danger to this technique: if the fill source is too small or too high you may get a distracting downward chin shadow. Here’s an over-exaggeration of that effect:

Argh. I’m not a fan of multiple chin shadows. They look “lit” to me and I’m not a fan of the “obviously lit” look.

Here’s a great fill position we haven’t spoken about yet:

Here the fill light is immediately next to the lens on the side opposite the key. Light from next to the lens will always reach into eye sockets, because if the lens can see eyes then the eyes can see the light immediately next to the lens. The only downside is that, like most of the techniques we’ve spoken of here, there will be two tones on the face: a bright (key) side and a dark (fill) side.

There’s one more technique, though, that can be a lifesaver. This is where the power of fill light becomes really apparent. Turn the page so we can talk about filling from the key side…

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The following image isn’t a true representation of what I’m trying to show as the 3D modeling program I’m using doesn’t replicate the effects of light perfectly.

This is supposed to look like sun coming through a window on the right side of frame with a bounced fill on the left side. Adding a bounce fill opposite the main light source is a common way to fill situations like this, but it has its drawbacks. The main one is that in order to catch the most light the card must be almost directly opposite the primary light source, and that isn’t always optimal for lighting a face.

If I’m going for a dramatic look then having very little light in front of the face is okay. If not, there are a number of cosmetic issues that have to be addressed:

If light is coming only from the sides then the center of the face goes dark. There are dramatic situations that warrant this, but on other occasions it can look like a mistake.

As I’ve mentioned before, the one place that almost never gets light from this situation is the corner of the eye closest to the nose on the key side: a key from the side doesn’t quite reach this spot, and the fill light from the opposite side can’t reach it either. Worse, this spot is made to look darker than it is by being juxtaposed against the key side, which is brighter than the fill side. This isn’t a huge problem with this virtual gentleman but it is very common in real life.

Moving the fill card toward the camera, and more frontal to the actor, may solve this problem, but unless this fill source is very big and a fair distance away it can feel as if a bounce card is just outside of frame. It’s rare in real life for that to happen.

What I often try to do instead is fill from the key side. This means that the primary fill source (yes, you can have more than one) is on the same side of the lens axis as the key is. Here’s an example:

All the light in the scene is coming from the right side of the lens.

Here’s the key light only:

Here’s the fill light only:

And, once again, the combination:

I really like this look for a number of reasons. The first is that there’s a greater tonal range across the face than if the fill was placed on the opposite side of the key. Instead of bright on one side and dark on the other, the bright side transitions into a dark tone which then transitions further into a darker tone. I like the richness of the multiple tones. I also like that the fill shadow is falling the same direction as the key. Filling from the key side means all the primary shadows in the scene are being cast the same direction, and this has a certain aesthetic appeal. It’s also possible to hide one shadow within the other.

The need for some sort of fill on the opposite side of camera doesn’t always go away. In this case the 3D software I’m using doesn’t wrap the light around this gentleman’s face as much as it would in real life. The virtual fill light for this shot is placed at the top right corner of the virtual camera’s matte box, so the really dark area of the face should be receiving more light and the dark side of the face should be a little brighter. If that shadow is a bit too dark then it’s easy bring it up subtly with a distant bounce card.

“Wait!” you say. “You’re talking about adding an additional light in addition to a fill card. Isn’t that needlessly complex and a waste of time?” To which I say, “No. Anything that makes the subject look good fairly quickly is a good thing.” I usually have a key-side fill light, often a tungsten source in a medium Chimera or aimed through a diffusion frame covered with Lee 216 or 129, on standby for exactly this kind of thing. If an actor lands near a light source during the master shot, say next to a window or a table lamp, and the angle of light on their face isn’t optimal, placing the fill light on the same side of the lens and making it optimal can clean up a lot of badness. If I can’t put the key in the right place for the shot then I’ll put the fill in the right place instead.

It’s a very smoothing, flattering look, and even though it adds an additional shadow it often “hides” within the shadow of the key and is less noticeable. Also, we’re more able to accept multiple shadows that fall in the same direction as opposed to shadows that fall in opposite directions.

Here’s a top view of our key + key-side fill setup:

You’re used to seeing this in real life when it happens like this:

Which would look something like this:

See the double shadows to the left of the subject’s head? That looks very realistic to me. In fact it looks more realistic to me than if it were a single source, because light in rooms often comes from multiple windows and multiple light sources and a little sloppiness can make the image more real.

Also, if you think about it, you’re emulating the look of a large source by replacing this:

With this:

We’re basically placing a light at each end of where the diffusion frame would be. You’ll miss a lot of the gradations that happen by having a light source that fills the entire space between the two lights, but you gain the possibility of doing this:

It’s very difficult to cut a large source off a nearby background. It’s much easier to cut one of two smaller blended sources off the background, which will reduce the brightness of the background considerably. We’re always trying to control light on walls as they are rarely very interesting to look at. Their brightness and prominence may distract from what we should really be looking at: the actor.

There are variations of this technique that I use all the time, depending on the subject matter. For example:

In this case the fill light is from directly below, as if sunlight was hitting the floor directly in front of this person. This is a little stark so lets add a small fill card opposite the key:

To me this has the feel of someone standing near a window where sunlight is streaming in and bouncing off the floor.

Filling from the key side doesn’t solve every lighting problem, but it solves a lot of them. I find it much easier to light a set once and not have to completely relight closeups if I can simply smooth out the light that’s already there, even if the key is in an awkward place for that one shot. The key-side fill usually doesn’t draw attention to itself, it blends in with the lighting that’s in place, it’s fast and it makes nearly everyone look good. What’s not to love?

All the 3D examples in this article were rendered in Poser 9.

Art Adams is a DP who prides himself on his natural look. His website is at www.artadamsdp.com.