Lighting - High Key and Low Key
After discussing contrast at a very top level view, I would like to introduce two twins, closely related to contrast - High Key and Low Key.
Both High Key images and Low Key images make an intensive use of contrast, but in a very different way. When approaching a shoot of a dramatic portrait, the decision of making it a High Key, Low Key or "just" a regular image has great impact about the mood that this picture will convey. While High Key images are considered happy and will show your subject as a tooth-paste poster; Low Key portraits are dramatic and convey a lot of atmosphere and tension. Let's explore those two dramatic lighting alternatives.
When looking at a High Key picture, you will probably notice two things right away. (Other than the happy-happy-joy-joy mood of the picture) The first thing is that the picture is bright. Yes - to create a high key image you need to set your exposure levels to high values. You will want to watch out, though not to over expose.
The other noticeable feature of High Key images is the lack of contrast. In addition for the tone being bright, you will notice that it is almost even across the scene. This is achieved by carefully setting the lighting of the picture. More about that later.
A third feature, that need closer attention to notice is the lack of shadows in the picture. The shadows cast by the model (or subject) are suppressed by lighting in the scene.
High Key image by moogs
Opposing High Key images are Low Key Images. In Low Key images the tone is darker, and the controlling color is usually black. There will be lots of dark areas in the picture. It is very common for Low Key images to give special attention to contour lines, emphasizing them with highlights.
Low Key images are also notable for a great deal of contrast that they display. Most notable is the rim light. A light surrounding the subject illuminating only the contour of the shape. So the contrast is between dark shape and bright contour.
Low Key image by ixelkhan
High Key, Low Key and mood - usually, High Key images are considered happy. They convey positive emotions, while Low Key images are darker and present drama or tension.
Happy High Key image by j_photo
Thoughtful Low Key image by .Bradi.
And here is your self assignment - for this week, your self assignment is does not involve taking any pictures. It involves careful examination of you surroundings. As I said before, Low Key and High Key are used to convey moods. Try to make some good use of your TV watching time; instead of couch potatoly looking at the ads, try and see which one are high key and which ones low key. try and analyze the adds in terms of darkness/brightness, shadows, background, and lighting. Keeping the images and results in mind will help you when we come to discuss of setups and results.