Apparatus and method for exposure of relief precursors

An apparatus for exposure of a relief precursor which comprises a substrate layer and at least one photosensitive layer, said apparatus comprising:

• a first light source comprising a LED array configured to illuminate a first side of the relief precursor, wherein the first light source substantially extends in a plane intended for being parallel to the relief precursor, and
• a second light source configured to illuminate a second side of the relief precursor opposite the first side,
• wherein the first light source comprises a printed circuit board having a black light absorbing surface facing the second light source, such that light reflected or transmitted in the direction of the first light source is absorbed at least partially by the black light absorbing surface of the printed circuit board.