An apparatus for curing photosensitive inks and coatings includes a lamp generating radiant energy containing ultraviolet radiation. The apparatus further includes a filter assembly receiving at least a portion of the radiant energy from the lamp. The filter assembly includes a body defining an open interior and panes located on opposite sides of the body to enclose the interior and form a chamber. An inlet and an outlet communicate with the chamber to provide for circulation of a fluid through the chamber. The filter assembly further includes a solid filter positioned within the chamber. The solid filter and the panes are transmissive to the ultraviolet radiation of the radiant energy generated by the lamp. The apparatus may include a shutter system having a plurality of opaque particles suspended in a liquid coolant for circulation of the particles through the chamber.