What are tattoo inks? Where in the skin is the tattoo? What happens when a tattoo is removed?

 

 

 

 

 

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The pictures are based on the article:

• To Tattoo or Not to Tattoo?,
  Henrik Petersen, Klaus Roth,
  ChemViews Mag. 2016.
  https://doi.org/10.1002/chemv.201600106