“No one checks the chemical composition of the colours, but our study shows that maybe they should.” Not exactly true. Part of the process of choosing the righ

“No one checks the chemical composition of the colours, but our study shows that maybe they should.” Not exactly true. Part of the process of choosing the right tattoo artist is making sure they use a quality ink, since this may significantly affect the final work. I agree most people don't really do it, and fewer care about the actual contents of the ink, but good tattoo artists will properly talk to customers about it, as to set the right expectations for colors that fade out quickly such as white or yellow, or change tone over time like old black ink.