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Which UV blacklight to choose for fluorescent decor

Fluorescent decor does not glow by itself: it needs ultraviolet light (blacklight). Choosing it well is the difference between a dull effect and a ceiling that lights up.

Wavelength

Look for UV LEDs between 365 and 395 nm. 395 nm is the most common and affordable and gives a visible violet tone; 365 nm is almost invisible and makes colours stand out cleaner.

How much power

• Tapestry or small corner: one 10–20 W UV LED bar or spotlight.
• 4–5 m canopy in a room: two 30–50 W bars or floodlights, one on each side.
• 8–10 m canopy in a venue or festival: four or more 50–100 W floodlights spread around.

These are guidelines: it depends on ceiling height, wall colour and ambient light.

Where to place it

• Light from below or from the sides, aiming at the piece, not at the audience.
• The less white light in the room, the stronger the effect.
• Two opposite sources avoid shadows and spread the glow evenly.

Common mistakes

• Incandescent «blacklight» bulbs: they get very hot and emit little UV.
• Placing the light too far away: intensity drops quickly with distance.
• Placing the light against the fabric: always leave distance and ventilation.