Guides

Blackout, semi blackout, light filtering, sunscreen: what the four fabrics actually do

The four opacity levels explained in plain language, including the two things people get wrong about blackout and the night-time privacy trap in sunscreen mesh.

Every blind on this site is labelled with one of four light levels. They are not marketing grades — they describe genuinely different fabrics, and picking the wrong one is the single most common reason somebody is unhappy with a blind that was otherwise made perfectly.

Sunscreen

An open-weave mesh. It cuts glare and a useful share of solar heat while leaving the view intact — in daylight you can see out and passers-by cannot see in.

The trap: that privacy is a contrast effect, not a property of the fabric. After dark, with the lights on inside, the bright side is now indoors and it reverses completely. Silhouettes are visible from the street. For a street-facing bedroom or a ground floor, either pair sunscreen with a blackout blind on the same window or choose light filtering instead.

Light filtering

Woven closely enough to hide the view, open enough to keep the room bright. Hard sun arrives as an even glow across the whole panel instead of a stripe on the floor.

This is the fabric that gives daytime privacy at close range — shapes show through, detail does not — which makes it the right answer for the Dhaka reality of a window twelve feet from another window.

Semi blackout

A dense fabric that stops most of the daylight but is not coated to kill all of it. At midday the room reads as evening rather than night.

It is the practical middle: enough for a nap, enough for a film, without the sealed feeling and stiff coated backing of true blackout.

Blackout

A coated fabric that passes no light through the cloth at all.

The two things people get wrong:

Blackout describes the fabric, not the fitting. A blind mounted inside the reveal must be 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.
It is not thermal insulation on its own. Blocking light is not the same as blocking heat. If heat is the problem, a honeycomb blind does more, and a blackout honeycomb does both.

Choosing in one line each

You want the view kept and the glare gone → sunscreen
You want brightness and daytime privacy → light filtering
You want to nap in the afternoon → semi blackout
You want to sleep past sunrise → blackout, mounted outside the frame

Still not sure? Tell us which room, which direction it faces, and what time of day it bothers you. That is enough for us to pick the fabric — it is the question we answer most often.

Frequently asked questions

My blackout blind still lets light in at the edges. Why?

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.

Can people see in through a sunscreen blind at night?

Yes, and this surprises people. Sunscreen mesh works by contrast: in daylight the bright side is outside, so you can see out and passers-by cannot see in. After dark the bright side is inside and that reverses — with the lights on, silhouettes are visible from the street. For a street-facing bedroom or a ground floor, pair sunscreen with a blackout blind on the same window, or choose a light-filtering fabric instead.

Do I measure inside the window frame or outside it?

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.