You know I thought this would be an easy question to answer. A mainly white picture with small amounts of detail in the dark. The opposite to Low Key. When I did my research on the internet I found that it was not so easy. Some people are very precious about what they will call ‘high key’. The high key status of quite a few images were challenged and found wanting. There are a huge range of opinions and definitions. I have made a rough list of different impressions that I encountered.
- Over exposed EV > 1
- Clipping of highlights – largely blown out,
- White back ground
- White subject
- White back ground and White subject
- Low contrast, few shadows
- Histogram moved to the right
- Increased setting for Key light
- Increased ratio of fill light to key light
- Monochrome effect
- Post processing adjustment
- Cinematography technique
There seem to be those who define high key by the lighting arrangement and those who define it in terms of the histogram. So which side do I take. Believe it or not I think both sides are right.
Historically the term high key refers to the key light – or the main light shining on the face of the subject. When this is turned up high, you get high key images. This was the principle lighting scheme in early cinematography as it allowed full view of the actor/ actresses as they moved and turned on the stage (similar to stage lighting).
The stock photo of “Beautiful girl with clean skin” demonstrates the typical histogram of a high key image. The use of a bright key light and a white background, overexposed with white light gave the characteristic right shift in the histogram. This is a very powerful image.
Interestingly the same histogram can be found in certain landscape images, where it is not possible to use key lights or to flood the back ground with flash. I think these images are just as deserving of the designation “high key”.
One type of image that I find less appealing is the washed out image. Although this fits the histogram definition of high key, there are no dark tones whatsoever in this image. The histogram is totally empty on the left. I would prefer a treatment that retained some of the dark shadows of the image. You will also note this image has no key lighting – it is in fact entirely back lit. I don’t however have a problem with this. I think it fits a broader definition of high key.
What’s the difference between overexposed and high key? I will preface by saying that this is my opinion. Overexposed images are washed out (no blacks) and are blown out (no details in the white). I don’t think High Key images should be washed out. They often have some blacks – but they do not dominate. I don’t think the subject should be blown out. Although some of the image is blown out (like the background) the subject often remains well exposed and within the gamut of tones.
Well there you have it. Is it high key? I believe it is if it looks high key, regardless of how that effect was achieved.
James Allan
Camera Clips 