Why CCTV fails at night, and how to fix it: IR, WDR and lighting.

Daytime demos look fine. Trouble appears after dark, or when sunlight pours through a door, and the footage turns into silhouettes.

The common causes

• Backlight: a camera facing a bright doorway sees dark faces.
• Headlight glare: vehicles wash out plates.
• Infrared reflection: IR light bounces back from a nearby wall or a dome cover.
• Under-lit areas: low light forces long exposure and motion blur.
• Wrong camera for the view: a wide camera cannot identify a face at distance.

Technologies that help

• Wide dynamic range (WDR) balances bright and dark parts of the same scene.
• Infrared illumination gives black-and-white night images at modest range.
• Low-light and colour-at-night sensors keep colour with little light.
• Smart IR and HLC (highlight compensation) reduce glare and blown-out areas.
• Thermal imaging works in complete darkness for detection.

The cheapest fix: light

Adding a little white light at gates, doors and counters often beats any camera upgrade. It supports colour, face and plate detail, and deters intruders.

Test before you sign off

Check each camera at its worst time of day. Export a clip, look at it on a normal screen, and ask whether a stranger could be identified. Adjust angle, exposure and lighting until the answer is yes.