Challenges in laser tattoo removal: the impact of titanium dioxide on photodegradation of yellow inks

As tattoos have grown increasingly popular, there has been an increase in their removal. This is commonly achieved using laser treatments. However, certain tattoo inks are resistant to removal using laser methods because of their composition. This includes the removal of yellow pigments and tattoo inks containing titanium dioxide (TiO₂). This research examined a series of yellow pigments (PY14, PY74, PY65) and tattoo inks, pre- and post-irradiation, with a QS Nd:YAG laser irradiation at 532 nm. The pigments and products were analysed using a range of techniques, including EDX-SEM, DLS, XRD and GC–MS. Results of this study indicate that the presence of TiO₂ alters the laser degradation process of the pigments studied, with observable changes to particle morphologies, particle size, and evolved volatile products. In addition, some of the degradation products were identified to be potentially harmful to the human body.