Abstract: A pair of front and back intensifying screens is disclosed capable of providing a sharp imagewise exposure of a dual coated silver halide radiographic element to light when the screens are imagewise exposed to X radiation predominantly of an energy level below 40 keV. The front intensifying screen is comprised of a fluorescent layer having modulation transfer factors greater than those of reference curve A in FIG. 3 and capable of attenuating by 20 to 60 percent a reference X radiation exposure produced by a Mo target tube operated at 28 kVp with a three phase power supply, wherein the reference X radiation exposure passes through 0.03 mm of Mo and 4.5 cm of poly(methyl methacrylate) to reach the fluorescent layer mounted 25 cm from a Mo anode of the target tube and attenuation is measured 50 cm beyond the fluorescent layer. The back intensifying screen has modulation transfer factors greater than those of reference curve B in FIG.

Abstract: The device provides an arrangement of the input and output ends of the machine which is of light and cheap construction, smaller in size and allows an adaptation of the machine in accordance with the width of the product to be treated. The device comprises, for each end of the machine, at least one rigid closing shutter carried by one of the frames of the machine. Guiding devices carried by this frame ensure a displacement of the or each shutter in a direction roughly perpendicular to the plane of the sheet passing through the machine. Devices for shifting the or each shutter are provided. The or each shutter cooperates by its free edge with the other frame of the machine so as to close in a substantially sealed manner the input or output end of the machine.