Why does my subject come out as a black silhouette against a bright window?

The camera meter is averaging the bright background to mid-grey and underexposing everything darker, including the face. Meter directly off the face instead, or add about two stops of exposure compensation so the skin is correctly exposed.

Should I use negative or slide film for backlit portraits?

Negative film is far more forgiving because it holds highlight detail and rewards extra exposure in the shadows, which suits backlight. Slide film has almost no highlight latitude, so it requires very precise metering off the face and controlled fill.

Metering and Exposing Backlit Portraits on Film

Shoot into the light and your camera will turn your subject into a silhouette unless you tell it otherwise. Here is how to meter and expose backlit portraits.

Backlighting places your light source behind the subject. Done well it wraps the hair in a bright rim, separates the person from the background and gives a soft, glowing quality that flatters skin. The problem is that your camera does not know what you are trying to do.

Why the meter gets it wrong

A camera's reflected-light meter, whether the built-in meter of an SLR or a handheld spot meter, is calibrated to render whatever it reads as a mid-grey. Point it at a bright, sunlit background and it will close the aperture and shorten the shutter to tame all that light. The face, which is much darker than the background, then falls several stops below correct exposure and records as a silhouette. This is exactly what happens if you trust a centre-weighted or matrix reading in a strong backlight.

Meter the face, not the scene

The single most reliable method is to meter the light falling on the subject's face rather than the whole scene. There are three practical ways to do this:

Walk in close. Move in until the face fills the frame, take a reading off the skin, lock that exposure, then step back and recompose. Do not let the bright background into the reading.
Use a spot meter. A one-degree spot lets you read the cheek from where you stand. Read a mid-toned area of the face and use that value.
Use an incident meter. Hold a handheld incident meter at the subject's position with the dome pointed back toward the camera. It measures the light landing on the face and ignores the background entirely, which makes it the most foolproof tool for backlit work.

If you can only use the in-camera meter

When you have to rely on the built-in meter reading the whole scene, add exposure. For a bright backlight, open up by roughly one and a half to two and a half stops from what the meter suggests. Dial in exposure compensation of +1.5 to +2.5, or in manual mode simply set a wider aperture or slower shutter than the meter calls for. It is better to give too much than too little.

Lean on negative film's latitude

Colour and black-and-white negative films hold highlight detail extremely well and prefer generous exposure in the shadows. Erring toward overexposure protects the face and still keeps the bright rim of light printable. Slide film is the opposite: it has almost no highlight latitude, so backlit slide work demands precise metering off the face and careful fill. For most portrait shooters, negative film is the forgiving choice here.

Add fill to control contrast

Metering for the face alone will lift the shadows, but the background may then blow out completely. Often that is a pleasing look. When you want more balance, add fill light:

A white or silver reflector bounced back into the shadow side returns light to the face without a second light source.
Fill flash set about one to two stops below the ambient exposure brightens the face while keeping the natural backlit feeling.
Position the subject so an existing bright surface, such as a wall or pavement, acts as a natural reflector.

Watch for flare

Shooting toward the light invites lens flare and veiling haze that lowers contrast across the frame. Use a deep lens hood, or have an assistant flag the sun with a hand or card just outside the frame. A little controlled flare can be beautiful, but uncontrolled flare will wash out the whole image. A clean front element and coated glass help considerably.

A repeatable workflow

Position the subject with the light behind them.
Meter the light on the face with an incident meter, a spot reading of the skin, or a close-up reflected reading.
Set that exposure manually so the camera cannot re-meter the bright background.
Add fill or a reflector if you want to tame the contrast.
Shade the lens against flare and shoot, bracketing a frame or two when the light is tricky.

Reading common situations

A few backlit scenarios come up again and again. Shooting a portrait against a bright sky at sunset, meter the face and let the sky record as a bright, glowing wash. With a subject in front of a window, meter the skin, not the window, and accept that the view outside will blow out. For rim-lit hair against dark foliage, a spot reading of the face gives a clean, well-exposed subject with a luminous edge. In each case the principle is identical: expose for the person and treat the bright background as a graphic element rather than something that must hold every bit of detail. Remember also to place the skin tone where you want it, giving fair skin a touch more exposure and darker skin slightly less, so the face reads naturally rather than washed out or muddy.

Meter for the face, expose generously and let the background glow. Backlit film, incident and spot meters, reflectors and coated portrait lenses are available at Boston Camera.