Blackout fabric blocks close to 100 percent of light. Room-darkening blocks roughly 90 to 95 percent, so the room goes dim rather than dark. Here is the part nobody mentions: even true blackout fabric lets light in around the edges, and that gap is caused by how the curtain is hung, not by the fabric.
What makes a curtain blackout
It is usually a layer. Either a separate liner sewn behind the face fabric, or a foam or acrylic coating applied to the back. Triple-weave fabric achieves it with a dense black yarn woven into the middle instead of a coating, which is why it drapes more like a normal curtain.
Room-darkening is the same idea with a lighter liner, or a tightly woven fabric with no liner at all. It cuts glare and most of the morning light without making the room feel like a cave.
Which one do you actually need
- Blackout — shift workers, babies and toddlers, a bedroom facing a street light, home cinema, anyone who wakes at sunrise in summer
- Room-darkening — most bedrooms, living rooms with screen glare, rooms where you still want to know it is daytime
- Neither — a room where you mainly want privacy; sheers or a lined curtain are enough
Why light still gets in
This is the real reason people feel let down by blackout curtains. The fabric is doing its job; the installation is not.
- Mount the rod high and wide. Ten to fifteen centimetres above the frame and twenty to thirty past it on each side.
- Overlap the panels in the middle rather than letting them meet edge to edge.
- Rod pocket or back tab beats grommets. Grommets leave scalloped gaps at the top by design, and that is where most of the light comes through.
- Go to the floor, or past the sill by at least fifteen centimetres.
If you need true darkness, a wraparound rod that curves back to the wall closes the side gap, which is the one thing a wider rod cannot fix.
The side benefits
A lined curtain is also an insulator and a sound dampener. Thermal blackout panels noticeably slow heat loss through a cold window in winter and keep afternoon sun out in summer. They will not soundproof a room, but they do take the edge off traffic noise.
FAQ
Is 100 percent blackout real?
The fabric can be. The window never is, unless the curtain seals against the wall on all four sides.
Can I wash blackout curtains?
Coated ones usually need gentle washing or dry cleaning, because the coating can crack. Triple-weave is normally machine washable. Check the label.
Do they make a room feel smaller?
Heavy dark panels can. Mounting the rod near the ceiling and choosing a lighter colour on the face side fixes most of it.
Every curtain at Crisp Fabric Co. lists its lining type and light-blocking level, so you can tell blackout from room-darkening before you order.
Browse the full range: Window Treatments
