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Davis, California

Saturday, June 15, 2024

The science of tattoos

Tattoos, once associated with people in the margins of society, such as sailors or bikers, are now a fairly popular form of body modification. In a 2006 report in the Journal of the American Academy of Dermatology, 24 percent of Americans aged 18 to 50 years old have at least one tattoo.

Tattoos combine medical skill and artistry in a way that is now accessible to nearly everyone. John Leal, a sheriff who has been a previous customer of Urban Body: Body Piercing and Tattoo in downtown Davis, said, “For me they have a religious meaning.” On one shoulder he has a cross with “John 3:16” written underneath; on his other arm he has the statement “Think Eternal.” Last Friday, he accompanied his daughter Jessica for her first tattoo.

“I just want one,” she said. “They have meaning to me.”

With tattoos now so common in America, do people understand how tattoos work?

The tattoo artist punctures the skin with a special needle in order to inject the ink. The tool contains a sterilized needle, a tube system that draws ink out from the machine, an electric motor and a foot pedal that controls the depth of the needle.

The layer of skin receiving the ink is important in the permanence of the art. The inner layer of skin, called the dermis, is the layer into which the ink is injected. The skin cells in the dermis are alive and stable which ensures that the tattoo will remain – sometimes with minor fading – for the rest of the person’s life.

Any kind of puncture carries with it a risk of infection, so the tattoo artist will do a great deal of work in order to decrease the risk as much as possible. During his training, Urban Body tattoo artist Chris Yoakum underwent classes about blood-borne diseases and safety practices, such as the use of the autoclave – a machine that uses temperature and pressure to kill bacterial spores.

“All of the needles are single-use and autoclaved by the manufacturers,” Yoakum said. “The materials that can be reused, like the ink tubes, are sterilized before and after every single use.”

An ultrasonic machine is used to remove particulate matter from the equipment, then autoclaved to remove all of the spores.

The customer’s skin is then shaved and disinfected.

The tattoo artist will start by stenciling on the person’s skin with pen to ensure smoothness of design when the skin stretches under the tattoo machine. Then, the artist will make the permanent outline of the tattoo using a small needle and thin ink. The outline is shaded using thicker ink and color is overlapped to ensure that there are no “holidays” – places where the color has lifted out due to the area healing or the artist missing a section of skin.

When the tattoo is completed, a disposable towel wipes up excess blood and the area is bandaged. Most bleeding stops within a few minutes. The sanitation precautions prevent the spread of blood-borne pathogens like hepatitis and tuberculosis.

When tattoo artists follow the correct sanitation procedures, the risk of an infection is very low, and according to the CDC there has never been a documented case of HIV spread through tattooing. However, there are still small numbers of unregulated tattoo settings, such as prisons or in the homes of amateur artists, who don’t use the proper equipment or sterilization procedures. Such practices can lead to a greater risk of infections like Hepatitis C.

Once the tattoo is in the skin, it can’t be easily removed. The method of choice for a regretful tattoo customer is laser tattoo removal. An intense light passes through the top layer of skin to selectively break up the ink pigments into fragments, which are removed by the body’s immune system.

There is no regret from Urban Body customers Jessica or John, however. Jessica’s chest now displays a rose and a rosary, adding her to the growing numbers of young Americans with body art.

AMY STEWART can be reached at science@theaggie.org.


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