ABSTRACT
Following on from the chapter on noise and sharpening, stretching is the logical step into the non-linear workflow. This is the magical moment when faint details are made permanently visible and the fruits or your labor become apparent. The familiar automatic screen stretch that we use for assessing manipulations on linear images can be applied to an image but rarely gives optimum results. The golden rule is to not over-stretch. Although global stretching is frequently required to set a baseline, it is often the case that further manipulation requires selective application. Stretching alters contrast and depending on the tool, localizes the effect based on brightness or scale. As such, some enhancements overlap with sharpening effects to some degree. To distinguish between the two, I consider image stretching operates at a scale of 32 pixels or more.
