Have a Tattoo? The Apple Watch Might Not Work For You

Some people with wrist ink say the Apple Watch can’t detect their skin

Sad face Apple Watch

Considering buying an Apple Watch? You might want to rethink it if you have tattoos. As Apple rolls out the long-awaited smartwatch, some users are finding their ink could be making their brand new gadget malfunction.

One Reddit user with a full-sleeve tattoo was about to call tech support after having issues with his Apple Watch: the notifications didn’t work and the watch would lock every time the screen went dark. At first, he thought it was due to a faulty sensor, but before calling for help he tried slipping the watch down to an untattooed part of his hand. All of a sudden, the watch worked perfectly.

It turns out the problem is with the light sensors the device uses to detect whether the watch is on someone’s wrist, writes Roger Fingas for Apple Insider. The sensors, which are also used to track the user’s heart rate, use a process called photoplethysmography: by flashing a series of infrared lights and green LEDs, the watch can detect blood flow beneath the skin, letting the little computer know if it’s being worn on a wrist.

In this case, it appears that the user’s tattoo is dark enough to block the sensors from getting a good read on his pulse. Fingas theorizes that could be a result of the pigments used in the ink:

“The issue could be down to the materials that tattoo ink is made from. Many pigment bases are derived from heavy metals, like mercury, copper, or nickel, which may interfere with the sensors.”

Apple's support page warns users that tattoos may interfere with the watch's heart rate detection system. And last month, Alexis Madrigal at Fusion reported that it's not just tattoos that might cause issues: anybody with naturally darker skin might find their watch malfunctioning. Madrigal points out that Apple may have totally missed this issue, since nearly all the people who tested the watch were probably white:

Like many technology companies, Apple’s executives form a key early testing team. The company’s top people become the company’s default customers. And if people with dark skin do have problems with the watch’s heart-rate sensor, none of Apple’s top executives would have experienced it.

The Reddit user was able to work around the problem by disabling the watch’s wrist detection at the cost of sacrificing some of the other features, like Apple Pay. In the meantime, it looks like some people might have to choose between dropping a few hundred dollars for the smartwatch or finishing off their tattoo.

h/t Apple Insider

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