It seems as though the Apple Watch isn't a big fan of tattoos, with a number of sensors not being able to function properly when there is a tattoo on the wrist of the user.
Apple has come out and confirmed that tattoos might interfere with a number of Apple Watch functions.
"Permanent or temporary changes to your skin, such as some tattoos, can also impact heart rate sensor performance," said the company on its Apple Watch support page. "The ink, pattern, and saturation of some tattoos can block light from the sensor, making it difficult to get reliable readings."
The issue is not exclusive to the Apple Watch as it can pose a problem with any device that uses light-sensitive sensors to calculate heart rate. Users of the watch who have tattoos have taken to social media, using the hashtag "#tattoogate" to express their frustration. In fact, the issue limits the watch's use in that it is supposed to automatically unlock when it detects that it is being worn. It often fails to detect this on the wrist of a tattooed user.
"My hand isn't tattooed and the Watch stayed unlocked. Once I put it back on the area that is tattooed with black ink, the watch would automatically lock again," said one user.
The sensors basically work because red blood reflects red light and absorbs green light. When the heart beats, the flow of the blood is greater and it absorbs more green light. As such, it makes sense that colored ink in the user's skin could affect how much light is absorbed.
Unfortunately, it seems as though some with darker skin might be experiencing the same issue as those with tattoos because of the fact that more green light is likely to be absorbed by those with a higher melanin content.
Users have reported the same issue with other devices from the likes of Fitbit. In theory, any device that uses light to detect heart rate would have the same issue. Despite this, many suggest that Apple's heart rate monitor is more advanced than most, even being capable of measuring blood oxygen levels. The device does not do this, however, seemingly because of a lack of FDA approval.
The issue with tattoos isn't the only one that Apple has experienced with the Apple Watch since its release. Apple has also been experiencing issues with its "taptic engine," from one of the two suppliers that makes the taptic engine, essentially leading Apple to have to scrap a number of units, in turn meaning that Apple is not able to meet customer demand as quickly as it should.
