Blackout Roman Blind

Because "blackout" describes the fabric, not the installation. The cloth itself passes no light, but a blind mounted inside the reveal must be cut a few millimetres narrower than the opening in order to move, and daylight finds that gap. If total darkness is the goal, mount outside the frame with a two to three inch overlap on each side and a deeper drop below the sill. Say so before we measure and we will size it that way from the start.

More than a roller, because the folds stack rather than wind onto a tube. On a tall window the stack can be a hand-span deep when the blind is fully raised, and that stack sits over the top of the glass unless the blind is mounted above the opening. If the reveal is shallow, mount it outside the frame or choose a honeycomb blind, which folds much flatter.

Both are valid, and they give different results. An inside (reveal) mount looks tidier and keeps the sill usable, but a little light always escapes at the edges. An outside mount overlaps the frame by two to three inches on each side and is the only way to get a genuinely dark bedroom. Tell us which you want and measure accordingly — our /measure guide walks through both with the exact points to record.

Every fabric fades eventually under direct sun; the question is how fast and how evenly. Solution-dyed polyester and sunscreen mesh hold colour far better than printed cotton-look fabrics, and mid tones show fading less than deep navy or black. A west or south-west window is the harshest position in a Dhaka flat, so if that is where the blind goes, choose a lighter mid tone and expect the visible side to soften slightly over several years rather than patch unevenly.