Inks get their color from the different chunks of minerals or metals they’re made up of — for example, black inks are usually made with iron, and yellow inks are usually made with cadmium. And it’s the chemical makeup of the ink that determines the type of laser a dermatologist needs to remove the tattoo, explains Khorasani.
"It's not uncommon for people to come in with multi-colored tattoos, where part of the tattoo responds well to a laser and other parts of the tattoo don't respond at all," he says. "That’s because every ink color is made up of different metals or minerals, which means each ink will only absorb specific laser wavelengths.”
The colors that are easiest to remove are black, brown, and blue, because those colors are the most commonly used for tattoos and there are a lot of different lasers built to remove them. But lasers are expensive and there's a limited amount of them available, so, according to Khorasani, this means dermatologists aren’t always going to have the laser required to remove a certain tattoo color.