Blackout is one of the few drapery briefs where the test is binary: either the room is dark enough to sleep through a Pacific Palisades sunrise, or it is not. The studio specifies blackout systems against that test, not against a fabric catalog.
The difference between a stock blackout curtain and a House of Drapery blackout system is at the edges — the side channel, the return bracket, the recessed ceiling pocket, the interlining that closes the gap at the heading. The fabric is the last thing we specify; the system is the first.
Specification references: fabric is chosen from the studio note on blackout fabrics and, for screening rooms, from velvet drapery fabrics; the window approach for wall-to-wall openings follows drapery for floor-to-ceiling glass. A built reference is the Beverly Hills traditional estate screening-room program.
From the mills: wool interlinings that close the heading gap are most often sourced through Holland & Sherry. The window approach for daylight-prone rooms with overhead glass is drapery for skylight-adjacent windows; further reading lives in the Bel Air estate primary suite study.