Apple Watch has issues with tattoos

Tattooed skin can interfere with the Apple Watch's wrist detection feature. Photo / Reddit, guinne55fan

If you've got a full sleeve, or just a bit of ink around the wrist, better think twice before spending up on a new Apple Watch.

After purchasing a new 42mm SS watch, reddit user guinne55fan suspected the device had a faulty wrist detector sensor when he didn't receive any notifications on the screen. He also found the watch would lock when the screen went dark - which should only happen when the watch is not touching the skin.

He suspected the problem could be related to his full sleeve tattoo, so tried moving the watch to a non-tattooed area - where the device worked perfectly. Turning off the watch's wrist detection feature entirely also solved the problem.

Apple explains on its support page that wrist detection works through light sensors on the back of the device. These sensors also serve as a heart rate tracker, using a method called photoplethysmography, which measures the absorption of light through the skin.

"Blood is red because it reflects red light and absorbs green light. Apple Watch uses green LED lights paired with light-sensitive photodiodes to detect the amount of blood flowing through your wrist at any given moment."

Tattoos - particularly those with dark, solid colours - appear to affect the device by reducing the reflection of light on the skin.

Apple has yet to comment on the problem, but do admit that various factors can affect the performance of the watch.

The Apple Watch has yet to be launched in New Zealand. Prices start at $349US ($458.77NZ) for an Apple Watch Sport, $549US (721.68NZ) for an Apple Watch and $10,000US ($13145.27NZ) for the upmarket 18-karat gold Apple Watch Edition.

- nzherald.co.nz