The newest lasers can remove tattoos by breaking up the pigments. The pigments absorb the laser wavelengths, with the colors matched to the target wavelengths. Short pulses of light from the lasers pass harmlessly through the uppermost layers of skin. The tattoo pigment becomes fragmented into smaller particles which are then removed by the immune system.
Side effects of laser tattoo removal are rare but may include hyperpigmentation or hypopigmentation. A scab may also appear on the treated site, but this will eventually fade away with time.