Fabric & light control
Solar screen vs light-filtering vs blackout (and the light-gap trap)
The fabric category — and, for blackout, the hardware around it — decides glare, view, privacy and darkness. Getting this right up front avoids the most common regret: a “blackout” shade that still leaks light.
The four categories
Solar/screen fabrics have an openness factor (the % of open weave): they cut glare and UV and keep your view, but are never dark. Light-filtering diffuses light for a soft glow with no view-through and isn't dark. Room-darkening blocks most light but not all. Blackout blocks essentially all light through the cloth.
Openness factor & privacy
Openness is the tell: 1% (99% solid) means more daytime privacy, more UV/glare block and a darker room; 5–10% means a brighter, clearer view with less privacy. The honesty point most sellers skip: openness only buys daytime privacy. At night, once interior lights are on, a solar shade at ~5%+ openness becomes see-through from outside. For nighttime privacy, pair it with blackout or drapery.
Why blackout shades still leak light
Blackout cloth is only half the story. A standard roller has a light gap around the edges and top, so even blackout fabric leaks light unless you design in side channels (L-channels), a fascia or valance, and returns — or pair with drapery. For a truly dark bedroom, spec blackout with side channels, or a dual roller (solar + blackout on one window).
Frequently asked
Do solar shades give privacy at night?
No. Solar-screen fabrics give daytime privacy only; at night, with interior lights on, they can be seen through from outside. Pair with blackout or drapery for nighttime privacy.
Why does my blackout shade still let light in?
The fabric blocks light but the gaps around a standard roller don't. Add side channels, a fascia and returns — or a dual solar+blackout system — for true darkness.
Keep exploring
Sources & methodology
This is an independent overview synthesized from official manufacturer and standards documentation — not copied marketing. We publish only what we can source, and flag anything that needs manufacturer or project confirmation. Specifications change; confirm details for your specific project.
- World Wide Shades — Roller shade openness (1/3/5/10%)
- North Solar Screen — Understanding solar shade openness & side gaps
Last reviewed: 2026-07-10
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