Abstract: An apparatus for the exposure of photosensitive plates on two sides, in particular for the preparation of printed circuits for electronic devices, comprises two similar exposure devices, mechanically connected and arranged adjacent to each other, each being equipped under a copying frame with an illuminating system, wherein a glass plate filling the format is arranged in the copying frame onto which a negative or positive master may be placed, together with a photosensitive plate above it, with a reversing station being associated with each of the exposure devices and both between each exposure device and the reversing station associated with it, and between the reversing stations a pivoting arm rotatable by 180 degrees each being arranged. The light source of each exposure device is arranged in or under the associated reversing station, wherein the beam of light may be conducted to the plate to be exposed of each exposure station.