A rumor about Apple Watch hit every one that Apple Watch could be broken by wrist tattoos or even stopping working.
Some users from Apple reflected that if you wear a watch on your wrist where covered by tattoos, then the watch would not work in some functions such as Auto Unlock.
What’s more, the sensor of Apple Watch will also become slow in reacting if your skin color is reaching black. But the solution for you is reversing the bottom of the LED brightness.
So, to buy or not to buy Apple Watch, that’s a question!