Abstract: A venetian blind which may have a conventional head rail, tilt rod, ladder tapes and slats, wherein a framework is mounted in the head rail and rotatably passes the tilt rod, an arm extends generally radially from the tilt rod for rotation with the latter, and a pair of stop members are selectively positionable relative to the framework in the path of arm movement for limiting arm rotation in opposite directions. The slats may be provided with reflective and absorptive surfaces to cooperate with the limiting positions of tilt for reflecting and absorbing heat in accordance with the seasons or other desiderata.