A gain correction and calibration technique for digital imaging systems is provided. In one embodiment, a method may include acquiring a plurality of dark images via a digital detector of an X-ray system. Acquiring the plurality of dark images may include acquiring data from a plurality of data channels of the digital detector during an analog test mode of the digital detector in which calibration voltages are applied to the data channels. The method may also include calibrating a channel gain map of the detector based on the plurality of dark images. Additional systems, methods, and devices are also disclosed.