A shutter assembly (1) for architectural openings (3), includes a first rectangular panel (5) hinged to a perimeter (9) of the architectural opening (3), and a second panel (7) hinged to the first panel (5). Each of the first and second panels (5, 7) comprises spaced parallel first and second vertical frame columns (17A, 17B, 19), and spaced parallel top and bottom horizontal frame beams (21, 23) connecting upper longitudinal ends and lower longitudinal ends of the first and second vertical columns (17A, 17B, 9) defining a rectangular perimeter frame. First and second rectangular plates (27A, 27B) are arranged within the rectangular frame in relative sliding arrangement. The first and second plates (27A, 27B) each have a pattern of apertures (29, 29A) complementary to one another, to provide an open position, in which the apertures (29, 29A) of each plate (27A, 27B) are in register with one another, and a closed position, in which areas without apertures of one of the first and second plates (27A, 27B) are in register with apertures (29, 29A) in another of the first and second plates (27A, 27B). Indexing means (41, 45, 47) are operatively interposed between the first and second plates (27A, 27B). The indexing means (41, 45, 47) are arranged to provide identical positions of adjustment of the first and second plates (27A, 27B) between the open and closed positions in each of a plurality of shutter panels (5, 7, 5A, 7A).