Blackout vs Room-Darkening

The call

This is a labeling trap worth understanding. "Blackout" describes the fabric, not the installed result — mount a blackout shade inside the window frame and daylight still rings the edges through the deduction gap. If a fully dark bedroom is the goal, the fabric is only half the answer: an outside mount with generous overlap, or side channels, is what actually kills the light. Room-darkening is the honest choice when you just want dimmer. Neither claim should be taken as "guaranteed dark." Confirm mount type and overlap before ordering; custom shades are generally non-returnable.