The term high key and low key lighting is regularly heard in photography circles but often misunderstood. In it’s simplest terms a high key image is a bright image full of light and mostly white tones whilst a low key image is a dark with minimal lighting and rich in black tones and lots of shadow areas.
However to understand the terms one would be better to think about the mood of the shot to be attained before looking at the relevant techniques. And whilst those techniques can be successfully achieved with natural light the terms high key and low key more commonly relate to induced mood lighting through studio or an artificial lighting set up.
So lets start by looking at the mood factor first (because let’s face it that’s the reason to choose either of these lighting styles in the first place) as mentioned high key lighting is bright and light but usually with the intention of invoking a feeling of freshness and optimism. It is often the choice of lighting for many pack-shot and product photographs that require a clean fresh feel to them, or portraits, catalogue and fashion work that need to “play it safe” with their image message. Although it is often a “play it safe” lighting set up, high key lighting is usually far more complex and requires many more lights than low key lighting to be achieved effectively.
Low key images are often more sinister in appearance and are usually used to achieve a classy, luxurious feel or a mysterious and edgy atmosphere to the image. Low key can be achieved with just one or two lights and a couple of reflectors but there is a fine line between a great shot and a lighting catastrophe for those who approach it with less than a methodical attitude, especially in a studio environment.
When talking about high or low key lighting many photographers, especially old pros, refer to lighting ratios and contrast ratios that harp back to the days of slide emulsions and 5x4 dark slides. And whilst lighting ratios can be determined and talked about, I personally departed from that way of approaching lighting in my studio when we went digital about 6 years ago. Why? Well it’s simple, these days studio lighting is not the dark art that it used to be; the calculations, the Polaroid tests, the light meters AND the lighting ratios all became largely redundant when the ability to preview the image full screen via a tethered camera arrived. Working with many advertising clients and in training other photographers I try to make it clear that achieving good photography is not about going into a studio and messing about to see what happens, it’s about making a decision about what the end result should be, understanding light, and then creating that lighting to make the anticipated result a reality. To do this with today's technology means we can gradually build up (or remove) the lighting step by step to achieve the desired result, visualising it on screen as we go along.
So how do we start to achieve the lighting in a high key studio set up? The first thing I do is determine what I would like my shooting aperture to be based on the subject matter, choice of lens and the depth of field needed. I then put two lights (one either side) at even power on a white background and adjust the power until I arrive at just below pure white (checking with the ink dropper tool that the values are below 255 in each colour channel) then I add 1/3 stop in power to bring my light just above white, resulting in a nice pure white background. By shooting a test with just these lights and the subject in place I can then check whether I have a silhouetted subject or if I’m starting to suffer flare (if I have flare I can add flags or reduce the light ensuring I still maintain white). Many photographers make the mistake of throwing all the lights on and not really knowing what’s going on or where problems might be originating. This is usually a big mistake as each light affects the other because of un-calculated bounce off of the surface of other softboxes and reflectors. Once I have established the correct background lighting for my scene I’ll then move to the key light and then the fourth of fifth lights, checking each individually and in combination with my other lights. For high key lighting I will often be using large scrims or softboxes to keep the lighting soft but I prefer a beauty dish and one harder light source to add some sparkle and avoid an image that is too flat or low in contrast which would result in a dull image!
For low key images, less lights are often used but precision is required in the application of the lighting to control important shadow detail. Successful low key lighting is often directed towards camera from behind the subject and is flagged to avoid spill and directed to bring out edge detail or a create a chiaroscuro effect. The skill is in making sure that the areas of importance are either pinpointed with controlled pools of low powered light or the careful application of reflectors. I like to use mirrored sheets or silver foil, shaped to focus light back onto the front of my subject via the lights from behind my subject.
You could of course take meter readings and mull over lighting ratios of 3:2: and 1:1.5 or 4:1 and apply the zone system to ensure you get the right tonal range in your final print. Or you could, by using the technology built in your camera, just get on with taking the photo by accessing what is happening before your eyes based on the predetermined result you have in mind.
To learn more about advanced creative lighting set-ups take a look at the tutorials in my Fashion and Beauty Lighting Secrets DVD where you can see many of the precise lighting set ups I use to capture professional images.
Words and images by Karl Taylor