There's an assumption that high-contrast images are more dynamic, more compelling, more inviting. Have a go at some low-contrast photography. You might surprise yourself with the results.
Mean and moody low-key photography
As a photographer, you're usually aiming to ensure that your photos are well-exposed and have an even tonal distribution. If you were to look at the histograms from these images, the data would be spread across them. Neither the shadows nor the highlights would be 'clipped', or have areas that are so dark or so light, respectively, that they contain no data. If you were to look at these images, they would look 'right', and be pleasing to the eye.
However, that isn't always going to be the kind of story that you want to tell. On occasion, you are going to want to convey a dark and brooding narrative, maybe even so far as to be menacing, that delves into darkness. You will look to shoot a low-key image.
Identifying low-key images
Low-key photography is a style of taking pictures that focuses on producing shots that mostly include dark tones—a person in a dark room with only a tiny bit of light on their face is a good example. You might have noticed how products are often shot using low-key photography, too.
If you were to look at the histogram of a low-key image, you'd see that the majority of the data are pushed towards the left-hand side. Don't worry that your shadows might be clipped: it's a part of the look.
Setting up a low-key shot
You're aiming for extreme contrast in a low-key shot, with most of the image dark or even fully black with just a little of subject highlighted to draw the viewer's eye. Since a lack of lack is your primary tool in taking a low-key photo, it's actually fairly easy to set up and while you do need extensive control over your light source, don't think that you require an elaborate studio.
One method of getting the low-key feel is to place the subject in a dark room, then turn the light on in an adjacent room. Open the door just enough to get the right amount of light on your subject, but not enough to light up the background.
Another means to getting a low-key feel is with candle-light, which can elicit a suitably gothic feel, or by using a torch. Torches are easy to direct and definitely cheap! If you want to start manipulating light in your photography but don't yet have the means or desire to go the whole hog with flashes or a studio set-up, low-key is a good option.
You will certainly need to be in manual mode in order to achieve a low-key shot. If you leave it to your camera to decide on optimal metering, it will try to over-expose the scene and ruin the effect. Using spot-metering to expose for the sliver of light, wherever it might be, is a good idea, too. This will help to keep that area light but the shadows dark.
The general rule is to keep things dark. Complete blackness around your subject (or even as part of your subject) is perfectly acceptable.
Processing low-key images
Ideally, the combination of manual control and carefully manipulated light means that you won't need to adjust the exposure beyond the odd tweak to the blacks or the highlights to ensure that they're sufficiently dark or light. It is worth considering converting your low-key images to black and white: initially, this can help you to identify and perfect the contrast in low-key images but over all it can help to increase the drama and mood in the photo.
More unusual ways of looking at things, remembering rules, and then breaking those rules, are in my lovely book, The Rules of Photography and When to Break Them. It's available as an e-book and in a dead tree version (UK, US).
What is key?
This week's Photography Fundamentals issue looks at key. Key is an element of the photography canon that crosses over with other artistic disciplines, most notably music and painting. I'm the least musically-talented person known to man, but even I manage to spot the similarities.
When we talk about the 'key' of an image we're talking about the range of tones or brightness that it comprises. Primarily we use it when we're describing images as being either 'high-key' or 'low-key', which are at the extremes of the range of brightness—light or dark respectively—and the feelings that these images convey. However, 'high-key' and 'low-key' can also be used to describe lighting set-ups, not just a style of photo.
High-key
High-key images are light and bright, either with upbeat and positive connotations or with dream-like, ethereal qualities. They will be low on contrast with very few, if no, shadows. If you look at a high-key image's histogram, it will exist mostly in the right half of the graph, with just about all of its pixels pushed above middle-grey and into the near-whites and whites.
The intensity of colours begins to fade as brightness increases, which means that high-key images are frequently black and white. If they are in colour, they tend towards pastels in tone. Or they could be the classic white-on-white.
It's easy to think of high-images as being 'just over-exposed', but getting them right is a bit more complicated than simply setting some positive exposure compensation. To achieve a good high-key image you need to bathe your subject in even light and keep everything about the image on the pale side. Unless you have deliberately blown-out the background to get it bright white, and with the exception of specular highlights, there will still be detail across the image.
I like to think of high-key images as the photographic equivalent of reading Jane Austen, but you can pick your own literary metaphor. Music-wise, it'd be a song composed in the major key.
Low-key
Low-key images evoke feelings that might be sombre or miserable, or even fearful or threatening. Like high-key images, they're low on contrast, but this time they are predominantly dark or black in tone and their histograms are clustered towards the left-hand side of the graph.
Anything that needs to be portrayed with a sense of impending doom is perfect low-key material. Just as high-key images aren't all about over-exposure, low-key images aren't focused on grisly under-exposure. There will still be detail in the shadows. If you don't want to be too purist about how your histograms look, having the odd bright area can strenghten the feel of a low-key image by re-inforcing just how dark the shadows are.
If you want a literary comparison, think gothic horror novels, or the minor-key for a musical equivalent.
High-key and low-key lighting
Cinematically, high-key or low-key lighting means something quite specific. High-key lighting has a low key-light to fill-light ratio that produces evenly lit scenes that are practically shadow-free. Low-key lighting, on the other hand, has a high key-light to fill-light ratio (yes, it's counter-intuitve) that creates pools of light and harsh shadows.
TL;DR
- Key refers to overall tone of an image
- High-key images are light and bright with a general sense of positivity
- Low-key images are dark, brooding, and can even feel menacing
- Although high-key and low-key images rely on technical over- or under-exposure to achieve them, this is controlled and does not negate details in the highlights or shadows respectively
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