It’s a question every designer, homeowner, and light-sensitive sleeper has asked at some point: Do custom blackout curtains really block all the light?

The short answer? Yes — they can block 100% of visible light, but only if the fabric or lining is genuinely engineered for it and the installation is done properly.

Let’s break it down.

The Real Deal on 100% Blackout

There are genuine 100% blackout curtains.

When tested with a torch placed directly behind the fabric, you won’t see any light source at all. That’s because true 100% blackout fabrics are engineered with special coatings or internal barrier layers that completely block visible light transmission.

However, not all blackout curtains on the market are equal. Many blackout fabrics offer very high performance — typically 90–95% light reduction — which works beautifully for most bedrooms, but isn’t technically complete opacity under strong direct light.

The difference lies in the technology.

What We Offer at Voila Voile

At Voila Voile, we clearly differentiate blackout performance levels — because precision matters.

We offer:

100% Blackout Curtain Fabrics

Our 100% blackout curtain collection features specially coated fabrics engineered to block all visible light. The coating technology ensures the curtain fabric itself delivers complete opacity.

If you test a sample with a torch behind it, no light source is visible through the fabric. The material is truly 100% blackout. View 100% blackout curtains.

100% Blackout Lining

We also offer 100% blackout lining, constructed using dense multi-layer coating technology (such as heavy 3-pass blackout lining).

This allows you to pair a decorative face fabric with a lining that guarantees absolute darkness — combining design flexibility with total light control. View blackout linings.

High-Performance Blackout (90–95%)

Alongside our 100% options, we offer blackout fabrics and linings that provide approximately 90–95% light reduction.

These are often woven with integrated blackout layers or feature lighter coatings. They perform exceptionally well for most homes, but may allow minimal light transmission under intense backlighting. View all custom blackout curtains.

So if your goal is true, complete blackout, choose either:

• A 100% coated blackout curtain fabric, or

• A curtain paired with 100% blackout lining.

Both options are available within our collection. 

Why 100% Fabric Alone Isn’t the Whole Story

Even when the fabric is 100% blackout, light can still enter around:

• Curtain edges

• The top near the rod or track

• Gaps between panels

• The bottom hem

That’s why professional installation and thoughtful design are just as important as the material itself.

How Designers Maximise Darkness

Precise Measurements

Custom sizing makes a significant difference. Curtains that are too narrow leave light gaps. We recommend panels that are 1.5–2 times the window width to create fuller folds that naturally reduce light leakage.

Layering

Layering adds performance and visual depth. Pairing decorative fabric with 100% blackout lining enhances both softness and total light control.

Hardware & Sealing

For nurseries, bedrooms, or home theatres requiring extreme darkness, curtain tracks, side channels, or magnetic edges help seal the curtain against the wall and minimise edge leakage.

Header Styles

Pleats, ripple folds, and wave headers influence how closely curtains sit to the window frame. The better the fit, the less light escapes.

Choosing the Right Blackout Option

When selecting custom blackout curtains, consider:

• Performance level – 100% blackout vs 90–95% reduction

• Fabric weight – heavier fabrics drape better and block more light

• Lining technology – coated multi-layer linings deliver maximum opacity

• Colour – darker tones naturally assist performance, though high-quality white 100% blackout fabrics are available

Beyond Darkness: Why Custom Matters

Ordering custom blackout curtains isn’t just about stopping light. It’s about:

• A tailored aesthetic — every fold perfectly measured

• Mood control — from bright mornings to cinema-style evenings

• Temperature regulation — many blackout fabrics provide thermal insulation

• Noise reduction — denser materials absorb sound and soften a room

Even if a room isn’t 100% sealed at the edges, the comfort difference is transformative.

Designer’s Take

Think of blackout curtains like architectural lighting control. The fabric technology determines whether light passes through, and the installation determines whether light slips around.

With the right combination of:

• 100% blackout fabric or lining

• Precise custom sizing

• Thoughtful hardware

In the end, a well-made custom blackout curtain doesn’t just block light. It shapes atmosphere, defines comfort, and creates that quiet, curated feeling you notice without even thinking about it.