An intro to High Key Lighting

Please note that high key is not just photographing someone against an overexposed white background – a lot of people refer to blitzed-out white backgrounds as high key photography but it’s only real high key if there are no dark tones, and the background doesn’t even need to be white for a shot to be high key.

The technique is simple, but it doesn't suit every subject.

Like most effects, High Key comes in and out of fashion. It used to be almost the standard method of getting rid of skin imperfections but most people find it easier to carry out 'skin repairs' on the computer.

At its most basic, high key is deliberate overexposure of the skin tones, and the subject normally has a bias towards light tones (although I’ve seen some outstanding examples of high key lighting on African Americans too). This overexposure reduces/removes the skin imperfections and produces a dreamy, innocent look - but it only works well if the skin doesn't look overexposed. So to make everything else in the shot look 'normal' and the skin light, we need to make everything else darker so that it ends up looking normal in the finished result.

Eye makeup and lipstick therefore needs to be much darker than normal, otherwise the whole shot will look overexposed. The background can be either white or grey. If you want it to appear white then you just overexpose it.

How much you overexpose it depends on the type/quantity of lighting equipment you have and on how much space you have.

Pure white background
If you want a pure white background you should start with a white or grey background and you need to light it so that it is overexposed relative to your subject.

If you have enough lights and take enough care to get the background perfectly evenly lit then a little bit of overexposure of the background, say ½ a stop (measured by reflected light) will do the job. But if you can’t get the background evenly lit then the level of overexposure will need to be higher, and many people advocate 2 stops of overexposure - but I don't, because of the problems it causes.

Let's look at some example taken with just one stop of overexposure on the background.

I photographed my favourite model, Louisa (unlike the person she's named after, this Louisa keeps perfectly still and never argues). Her synthetic hair is a bit less tolerant to lighting faults than real hair, and a human model photographed in the same way as the shot on the left would be fine.

When shooting against an over-lit white background, there are three major problems that need to be avoided... 
1. Wraparound effect
2. lens flare
3. Damage to edge detail.

Wraparound is light spilling on to parts of the subject from the lit background. The larger the background and the closer it is, the greater the problem - so if you want to avoid wraparound, don't put the subject too close to the background! Here's our first example, with the model just 2' from the background...

Lens flare is caused by unwanted bright light striking the lens. Some lenses are more prone to flare than others, but the problem can be reduced with any lens simply by using a good lens hood and by keeping the level of background overexposure to the minimum.

You can see that the edge detail has been pretty well destroyed by the light on the background, and the other problem of light wraparound is very obvious too - in fact all of the light you can see on the mannequin is wraparound light from the background because the subject itself is totally unlit. Here's a closeup of the right side

So, let's double the distance to four feet from the background.
Doubling the distance from subject to background helps to solve both of our problems.
It helps to solve the wraparound problem because the increased distance means that the background is much smaller in relative terms, so there is less unwanted light coming from the sides, top and bottom of the background.
And it helps to solve the problem of the edge detail being destroyed because when the light has twice as far to travel it loses most of its power.

So here's the effect of light wrapping around our model and destroying edge detail at a distance of four feet. As you can see from this enlarged situation, it's far less bad now but still far from perfect. Let's move 'her' to eight feet from the background, because that's a distance that will be great enough for these problems to become far less dramatic.

OK, it still isn't perfect - we would need to at least double the distance again to avoid all possible problems from the background - but at least we've reached a workable compromise between the ideal working distance and the amount of space available to most people.

And now it's time to light our model.
Whenever we light any subject against a white background we need to remember that we are in fact photographing two separate subects - our main subject and the background - and we must always light just the background first (as in the examples above) to check that the background is in fact as white as we want it to be and that light from the background hasn't damaged our main subject too much.
So, here's our shot with both the subject and the background lit. I used a single light, a 70cm beauty dish, to light the subject. No hairlight, no fill light, not even a reflector. You can see some damage to the fine edge detail but not too much. The shot below right was taken at the same time but I switched off the flash on the background to produce a totally unlit background.

It shows the subject with almost the same lighting (a hairlight from a snoot has been added) and you can see fine detail in the hair that is missing from the white background shot.

You can also see that the overall contrast is higher in the unlit shot, this is due to the complete absence of flare and the complete absence of any unwanted light from the background.

There are quite a few different ways of lighting the background evenly.
1.You can aim two softboxes (preferably rectangular or striplight ones) at it, one either side. Point the one on the right to illuminate the left side, and vice versa.
2.Or do the same thing with a pair of umbrellas, but use reflective umbrellas for this, not shoot through ones, otherwise the light will spill everywhere.
3.Or you can use standard reflectors, arranged the same way – but there will be hotspots using this method, so 4 will do a much better job than 2.
4.Or use the special background reflectors produced by Lencarta, Elinchrom and Bowens. They are angled at 45⁰ so that they illuminate the background perfectly, they also need far less space than any of the other options. You’ll probably need a pair of them for groups, but one is often enough for a portrait of just one person, and just one was used for the example shots above.

An alternative to lighting the background is to buy one of the commercial ‘solutions’ available, for example there’s a softbox arrangement that acts as a background… but although the lighting in the softbox can be pretty even, it can still cause flare and it can still degrade the edges of your subject – and anyway, these products are often too small and are expensive.

Lighting for high key
The lighting for genuine high key photography is very simple - just use large diffused light sources very close to the subject to avoid harsh shadows and reflections on the skin. Avoiding reflections is essential because skin reflections will burn out with overexposure. The 'high key' lighting of family groups as practised in some modern commercial portraiture firms isn't really high key at all, but it uses general high key principles - there are normally 2 lights on the background, illuminating it evenly and causing enough overexposure for some light to bounce back on to the subjects, providing some controlled backlighting.

Then there are 2 more lights on the subject, usually a family group, and the lights are placed slightly above and to each side of the subjects.

This results in very flat lighting (which gives everyone a fat face!) but it has the advantage that nobody can accidentally create shadows onto anyone else, and the lack of shadows contributes to the high key effect. A useful side effect is that very little lighting skill is required – which also makes this technique popular with beginners.

Light spill from large light sources
Obviously, high key lighting normally involves using large, diffused light sources such as softboxes, shoot through umbrellas or scrims and this can cause its own problems

Softboxes are the most efficient large light sources (because all the light is travelling in just one direction, or at least in theory) but of course it doesn’t just get to the subject and then stop – it goes past the subject and bounces off the background, it spreads out and bounces from the walls and ceiling too. In fact, there’s a great deal of ‘bounce’ – at a distance of 12’, a 3’ x 3’ softbox creates a spread of light 25’ high and 25’ wide!



So what happens to that bounced light?
It goes everywhere, or at least it does in a small studio.
For beginners who are just trying to get very soft lighting, this may seem to be an advantage of sorts – but once you’ve moved past the soft lighting stage and you want more controlled lighting, you’ll want to control your lights – and you’ll feel frustrated that whatever you do you’ll find that bounced light has lowered the contrast, caused lens flare and stopped you from creating the shadows that are needed to shape faces and add interest..

So, what can you do about it?
Well, some people think that the answer is to put a honeycomb (grid) over the front of the softbox. These honeycombs are ridiculously expensive and you may want to think carefully before you spend your money.

What the honeycomb will do is to control the spread of light. If you get a fine one with a 20⁰ angle then the spread of light from our 3’ x 3’ softbox at 12’ will reduce from 25’ to 8’ – but it will also lose its wrap around qualities, the shadows will be much harsher and it will give an effect much more similar to a beauty dish than to a softbox. It will also ‘lose’ around 4 stops of lights so, for example, your 300 Ws flash head will only produce the equivalent of 16 Ws!

There are really just 4 possible answers that work.
1. Use a large studio. If you have a high ceiling and if the walls are distant, bounced light won’t be a problem – but of course this ‘solution’ simply isn’t practical for most people.
2. Paint the walls and ceiling black. White paint is the worst possible studio decoration because of the ‘light bounce’ problem. Black is the best. But studios with black walls and ceilings are depressing places to work in and anyway, it isn’t a practical solution if your studio has to double as your living room…
3. Paint the ceiling black and have black drapes that can be pulled across the white walls when required. This is probably the ideal solution for high street portrait studios that need to look cheerful but which also need to work, but again it isn’t practical if your studio is also your living room.
4. Make do with what you’ve got, but gain control of bounced light by using flags. Flags are simply pieces of black painted card or board, or better still cinefoil. Place flags wherever they need to go to stop light bouncing around and ruining your shots. The look untidy and it takes time and a bit of thought, but it’s the only way of controlling light spill in a small space with light coloured decoration. And it’s cheap!

I mentioned shoot through umbrellas and silks too. The light spill from these is far worse than with softboxes and although you can use flags, in exactly the same way, it’s a bit more difficult to control all of the light spill.

Reflective umbrellas are popular and the light spill they produce is about the same as from a softbox of similar size – but they can’t produce soft light when required simply because they face the ‘wrong way’ and so can’t be placed close enough to produce soft light.

Which leads me on to my final point about limiting light bounce and getting soft lighting…

The light needs to be close, or it won’t be soft. It needs to be so close in fact that it will be physically in your way. Work around that, but don’t move the light further away to make your life easier, unless your softbox is truly massive.

And, by having your softbox really close, the effect of the bounced light will be reduced.

The reason for this is that the further the light has to travel, the more power it loses. If the light that reaches your subject only has say 3’ to travel and the light that bounces off the nearest wall has 6’ to travel then a lot of the power of the bounced light will be lost in travelling 6’ to the wall and another 6’ back again. And some of the light will be lost in reflection too, probably no more than about 70% will actually reflect from any surface except a mirror.

©2008 Garry Edwards, www.photolearn.co.uk