For single colour tattoos, red and black ink responds the best to the treatment. If your tattoo is in one of these inks, you can expect excellent results compared to those with multiple colours or any aside from red and black.
It is possible to get very good results for multi-coloured tattoo removal too. Green, blue, purple and orange inks are the most resistant to the laser treatment, but this can be difficult to predict due to the variations of inks used within the tattooing industry.