Intensity adjustment is seen as so very important that many console manufactures include a dedicated intensity wheel on their desks. This wheel is always active for dynamically adjusting intensity anytime a fixture or group of fixtures is selected. Typically, this will be an absolute adjustment, but most consoles also come with a key that can be held when adjusting the intensity wheel. This key will change its behavior to a relative adjustment. With relative adjustment enabled, turning the wheel 10 percent of its range will increase all selected fixtures intensities by 10 percent of their current value. So a fixture with no intensity will not increase, while a fixture with an intensity of 50 percent will increase to 55 percent. Conversely, if you had instead used a traditional absolute adjustment, you would have seen the fixture with no intensity rise to 10 percent and the 50 percent fixture rise to 60 percent.
—Brad Schiller, from “Feeding the Machines,” PLSN, Feb. 2014
