In 2012, a Harris Interactive poll reported, one out of five US adults had a tattoo—and 14% of those polled wished they could take it back. Through laser tattoo removal, they might be able to do just that. The job of a laser system configured to fade tattoos is essentially to make the tiny granules implanted by the tattoo needle beneath the skin even smaller. During removal, the device emits short pulses of light whose wavelength is calibrated to be absorbed only by certain colors. The ink absorbs the energy from this light, heats up, and breaks down into fragments small enough to be escorted away by the immune system’s tiny bodyguards.
Certain pigment colors are easier to remove than others: black pigment is the easiest to remove because it absorbs all laser wavelengths, whereas yellow is one of the most difficult because it only absorbs a very specific wavelength. The tattoo’s location also affects how completely it can be removed: tattoos closer to the heart benefit from rapid blood flow that can quickly carry away ink fragments and sad memories.
In the decades before lasers, the main option for removing tattoos was simply abrading the skin, which always carried a risk of scarring. Further back, centuries-old historical accounts discuss a diverse array of removal tactics, from covering skin with saltpeter and turpentine in ancient Alexandria to stretching the tattoo while rubbing it with green corn juice among the North American Chickasaw people. In the future, all tattoos may be more temporary: new tattoo inks are being developed that encapsulate the pigment particles in microscopic beads designed to easily rupture under a single laser pulse. For now, however, multiple treatment sessions are almost always necessary.