If you have seen images that have white backgrounds, and with no hard shadows on the subjects, most likely these are high key photographs.
Although, you can achieve a “high key” effect through post-processing, you can also certainly do it in-camera, as preferred by many photographers who want to practice their lighting techniques.
The term “key” refers to the key tone in a photograph, which is the midtone (a medium gray). When it is placed high on the exposure scale (hence the term “high key”), the dark and light tones are also moved towards the highlights (to the right of the camera histogram). This makes light areas lighter or white, and the dark areas have much less shadow.
Here are some pointers on how to create high key photos:
Light up the background – high key images usually have white backgrounds with hardly, or without, any details. In a studio setup, this can be achieved by shining two lights on a white backdrop, one on each side of the subject. The subject should ideally be a few feet away from the backdrop to avoid its shadow from falling on it. The lighted white background should look like an empty, white, almost glowing space exists behind the subject.
Control the intensity of the fill light and key light – place the key light in a spot to the preferred side of your subject and a little to the front. Place the fill light on the opposite side of the subject. The key light, which is the main light source for your subject, should ideally be as bright, or twice as bright, as your fill light. All these lights, including the background lights bouncing off the white backdrop, gets rid of harsh shadows and gives the image a light color palette. Make sure your lights are not too overpowering that they run the risk of creating unwanted blown out highlights on the subject.
Use window light as a natural light source – light streaming in from a window can be effective in creating that soft white background. You can cover the window with thin white fabric to hide window pane details and to get a more balanced whiteness and brightness.
Use your camera’s histogram as a guide – the histogram is a graph that shows the brightness levels of the scene. You can view it on the LCD screen of your digital camera if it has one. This graph generally looks like a hill with peaks to show how tones are being distributed. The left of the histogram represent the dark areas and the right represents the highlights. If your “hill” is mostly towards the right, then your scene might be too bright and could be overexposed from all the lights. Take note that overexposure does not mean “high key.” Unlike high key photos which preserve most of the subject’s details, overexposure can cause details to disappear.
Manually adjust the camera exposure – set your camera to Manual mode and increase the exposure setting by a stop or two. This will set the midtone to a higher brightness level which adds to that high key effect.
There is no single exposure setting for creating high key images and you can play around with a number of elements, from the shutter speed to aperture to degree of brightness. You can also overexpose certain parts of your subject while keeping the essential areas detailed. Be creative with your compositions while keeping the essence of the high key treatment.