A radiographic imaging apparatus for taking X-ray images of an object includes a front panel and back panel. The panels have substrates, arrays of signal sensing elements and readout devices, and passivation layers. The front and back panels have scintillating phosphor layers responsive to X-rays passing through an object produce light which illuminates the signal sensing elements to provide signals representing X-ray images. The X-ray apparatus has means for combining the signals of the X-ray images to produce a composite X-ray image. Furthermore, the composition and thickness of the scintillating phosphor layers are selected, relative to each other, to improve the diagnostic efficacy of the composite X-ray image. Alternatively, a radiographic imaging apparatus has a single panel having arrays of signal sensing elements and readout devices and scintillating phosphor layers that are disposed on both sides of a single substrate.