Step wedge
A printed series of density increases, in regular steps from transparent to opaque. its a method of making exposure tests when enlarging.
The following experiment was carried out to support the theory of migrating silver particles: A photographic plate was exposed through a step wedge. Meanwhile, a plate coated with a film of gelatin was soaked in a metol developer.
For these tests, a Transmission Stouffer Step Wedge target (see Figure 1) was photographed. This target is a piece of film with a series of gray patches (i.e., wedges). The wedges run from very dark tones on the left to very light tones on the right.
Our Dynamic Range measurement system involves shooting a calibrated Stouffer Step Wedge (13 stops total range) which is backlit using a daylight balanced lamp (98 CRI).
When I ran (secret) step wedge tests and checked them in a densitometer, they were dead-smack on. If you're a geek, they'll read your tests on their densitometer for you.
2 Step Wedge (21 step), there is an increase of about 0.15 in density between each step or an increase of 50-percent density. The individual steps should be calibrated by reading the step on a densitometer for the greatest accuracy.
to the original design or copy to determine accuracy of exposure and uniformity of color separations. Patches of yellow, cyan and magenta are included with the scale when photographing for color separations); also referred to as gray or step wedge.
 See also: Light, Value, Camera, Exposure, Image
  
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