Regardless of the reason for which you require darkness in your home during the daylight hours, whether it be you have a young child who naps during the day or you work atypical hours and require sleep during the day, or you have a home theatre, light leaking into your room can be a real nightmare.
Choosing a blackout roller shade is an effective way to block the light during the daytime. However, even if you install an blackout window covering, light will still seep from the edge of the window which cannot be completely sealed due to the manufacturer having to subtract 1/8 of an inch. This is even more true when your blind is installed inside the window frame. By design, the canvas mechanism is wider than this. These small spaces exist to prevent the canvas or fabric from rubbing against the edge of the window when pulled down and thus damaging the canvas.