So in four years of development, Apple has not once tested this on tattoos?
Don't have a tattoo (on my wrist) and don't give a hoot...
The sensor used by the Apple watch is similar to sensors used by everyone else's watches. Physics dictate the way they work.
For the .00001% of the population with a dark tattoo on your wrist, return watch and consider there are consequences to tattoos, piercings, general body modifications. Some are obvious, others subtle.
Can we have some real news?