Brain and Body

The Science Behind Laser Tattoo Removal

December 16, 2015 | Kelly Tatera

Laser tattoo removal using Q-switch laser
Photo credit: Smarter Every Day/Youtube

The painful price to pay for regret.  

Getting your “soulmate’s” name tattooed on you seemed like a great idea when you were certain you’d be together forever, but after that didn’t go as planned, that permanent ink etched into your skin has got to go.

Laser tattoo removal sounds like a simple solution to the problem, but the process is actually a lot more complicated than you may think. You may have seen Smarter Every Day’s video about the process of getting tattooed, but they decided to make another one investigating the laser removal process.

According to the video, tattoo ink can be pretty stubborn since the inks tend to be made of compounds from heavy metals like lead, copper, and manganese. These metals are what gives the tattoos their permanence, so to remove it, those ink particles must be broken up by lasers.

SEE ALSO: Tattoos: The Science Behind the Permanent Body Art

The removal lasers, also called ultra-short pulse lasers, are extremely hot and work in a rapid manner. The removal laser in the video is called a PicoLaser, and it works on a scale of “picoseconds,” or a trillionth of a second. It’s hard to even imagine a trillionth of a second, but the extreme speed and heat are critical to break up the stubborn ink particles.

The process that breaks the particles apart is called photothermolysis, and it’s the same process used in laser hair removal. Basically, the ink particle must be heated so that it expands, but the zap of the laser has to be quick and precise enough to leave half of the particle cool. Then, the opposing forces of hot and cool cause the ink particle to rip apart.

The final step occurs after the ink particles have broken apart into chunks. Once they’re small enough, they can be absorbed by the white blood cells and transported to the liver. The reason that a tattoo fades throughout time is actually because of the white blood cells. Armies of white blood cells are sent to try and engulf the foreign invaders, but since many of the ink particles are much larger than the white blood cells, they’re too big to be grabbed and removed from the skin. Instead, all of the work by the white blood cells just leads to an eventual fading.

When it comes to tattoo removal, black color pigment is the easiest to remove since it absorbs all laser wavelengths. Color, on the other hand, can only be treated by certain lasers based on the pigment color, so it can be a much lengthier process. Depending on the size and color of the tattoo, it can take anywhere from two to 10 sessions to fully remove it. In some cases, laser tattoo removal can leave behind scars.

So as you can see, the tattoo removal process can be time-consuming, painful, and costly. Everyone has their own reasons and inspirations for getting tattoos, but if your reasoning involves the thought that you can simply get the tattoo removed later in life, it’s probably best to hold off. Perhaps the technology will evolve and future removals won’t be as complicated, but until then, you should go into it with the mindset that tattoos are forever.

Check out Smarter Every Day’s slow-motion take of the laser tattoo removal process.



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