There is a lot of science behind removing a multi-coloured tattoo by laser. The reason why multi-coloured tattoos are far more difficult to remove than black tattoos is because different colours of ink pigment absorb different levels of energy before they shatter. Black is the easiest pigment to remove, because it is the darkest and absorbs the most energy. Green, blue and yellow are some of the most difficult. In the past, this has meant that multi-coloured tattoos required complicated (and costly) treatment regimes, using different lasers to treat different colours.
Now, with the latest advances in medical-grade lasers, specifically the PicoWay laser, we are able to effectively treat multiple colours at the same time and on all skin types.