Dark tattoos can throw off Apple Watch's heart rate sensor

Here's one factor to take into account if you're still undecided about getting the Apple Watch: it doesn't seem to play well with tattoos. Several users revealed online that their devices act wonky when worn on a tattooed arm. The heart rate sensor wouldn't read their pulse, and the watch wouldn't detect direct contact with the skin, causing apps to stop working and repeatedly ask for the passcode. To confirm if inked skin really does affect the smartwatch's functions, iMore has decided to perform a series of tests. "[W]e're inclined to agree with those early reports," the publication writes, "if your tattoo happens to be a solid, darker color."

Engadget