Where to begin
Christoffer suggests that if you’re a novice with double exposure, it is good to start with two frames. Using something as simple as your own hand against a bright background and clouds on a moody day is a good start. This kind of experimenting will give you a quick understanding on how the exposures blend. Remember, the exposure can only get brighter, therefor an overexposed area will remain overexposed even if you underexpose your next frame. From there on it is all about experimenting and adjusting to what fits your style.
The importance of light
In any form of photography lighting is crucial to achieve a great image. When creating such extensive silhouttes within an image it is no different. A background bathed in natural light is ideal but when the weather does not permit, Christoffer is quick to use a Nikon speedlight or two, paired with a foldable diffuser large enough for full body portraits.
High contrasting light is often a good thing. For nature images, Christoffer usually underexposes the foreground and overexposes the background. When there is overexposure in both multiple exposed frames, the composition becomes more surreal, as the original silhouette gets a new contour or shape.