A large majority of photographs contain a wide mix of tones from shadows to highlights and, primarily, everything in between. That means that images at the extremes—composed primarily of light tones or dark tones—are inherently more interesting than the same old thing. There’s a name for these images at the extremes. Images comprised of shadows and dark tones with minimal highlights are called low key, while the opposite—images made up mostly of light tones with fewer shadows—are called high key. These high key and low key looks make for interesting photographs, especially when it comes to portraits. Here’s how to use subject matter, lighting and retouching to shift the key as needed on demand.
Whether the aim is a high key or low key photograph, the process begins with the actual tones in the scene. In practice, this means that for a high key photograph, it’s best to start with a subject wearing light-colored clothing, in light-colored surroundings, with bright, even light. Harsh light creates more pronounced shadows, and that hampers the high key effect. For soft, even lighting, consider working outdoors in lightly overcast skies or using a large softbox or bounced light indoors.
The reverse is true for low key photographs. By starting with a subject in dark clothing and dark surroundings, the process of creating a shadow-rich photograph is simplified. Instead of the broad, even lighting useful for high key images, try using a smaller source—like a small softbox or even a bare bulb—in order to create dark, dramatic shadows. Focusing the light through a snoot or with flags and other modifiers can help to minimize the spread and further pronounce shadows. Even the unfiltered sun can produce a low key image if the subject is positioned correctly. Whether working with strobes or sun, try positioning the subject such that the light comes from the side or even from behind them in order to create the kind of edge lighting that reveals a preponderance of dark tones to the camera.
When lighting control is limited or when the shoot is happening outdoors, consider using the camera controls to help shift the key of the image. When working with the sun, for instance, underexposing enough can actually make daytime look like night. Slightly overexposing a light-colored subject can shift the key upward, which often has the additional benefit of hiding skin texture and blemishes.
Ultimately, it’s all about the highlights and the shadows. Surprisingly, though, it’s the shadows in the high key image and the highlights in the low key shots. Because in a low-key image made up predominantly of shadows, a small amount of highlight takes on paramount importance. Conversely, the few shadows in a high key image had better be carefully placed. A single light source makes this simplification not only easier but also more effective, and fine-tuning in the computer is also immensely helpful. Something as simple as adjusting the sliders for shadows and highlights in Lightroom will ensure black tones are truly black, for instance, or help to keep bright highlights from blowing out. With high key shots, ensure shadows aren’t too heavy, and with low-key images, ensure the highlights are bright enough to provide the necessary contrast.