A blind for a building opening, and having a head rail, attachable adjacent to the building opening; a first blind panel stored in the head rail, and adapted to be lowered as a loop defing two loop parts, over the building opening; a second blind panel stored in the head rail and adapted to be lowered over the building opening, and wherein the first panel is formed of light permeable material, whereby to admit at least some light into the interior of the building, and the second panel is formed of light impermeable material; transverse blind strips on the first panel, at spaced intervals there across; and, blind panel control mechanism in the head rail whereby the first blind panel loops can be adjusted so as to adjust the transverse blind strips between open and closed positions.