Modern tattoo machine in use: here outfitted with a 5-needle setup, but number of needles depends on size and shading desired

Some tribal cultures traditionally created tattoos by cutting designs into the skin and rubbing the resulting wound with ink, ashes or other agents; some cultures continue this practice, which may be an adjunct to scarification. Some cultures create tattooed marks by hand-tapping the ink into the skin using sharpened sticks or animal bones or, in modern times, needles. Traditional Japanese tattoos (Horimono) are still "hand-poked," that is, the ink is inserted beneath the skin using non-electrical, hand-made and hand held tools with needles of sharpened bamboo or steel. This method is known as "Tebori".

The most common method of tattooing in modern times is the electric tattoo machine, which inserts ink into the skin via a group of needles that are soldered onto a bar, which is attached to an oscillating unit. The unit rapidly and repeatedly drives the needles in and out of the skin, usually 80 to 150 times a second. This modern procedure is ordinarily sanitary. The needles are single-use needles that come packaged individually. The tattoo artist must wash not only his or her hands, but they must also wash the area that will be tattooed. Gloves must be worn at all times and the wound must be wiped frequently with a wet disposable towel of some kind.

Traditional two coil tattoo machine

Prices for this service vary widely globally and locally, depending on the complexity of the tattoo, the skill and expertise of the artist, the attitude of the customer, the costs of running a business, the economics of supply and demand, etc. The time it takes to get a tattoo is in proportion with its size and complexity. A small one of simple design might take fifteen minutes, whereas an elaborate sleeve tattoo or back piece requires multiple sessions of several hours each.

"Stick and poke"

A technique often used for home-made tattoos is "stick and poke". The tip of a sewing needle is wrapped in ink-soaked thread, leaving only the point protruding. Keeping this simple instrument saturated with ink, the skin is pricked over and over, creating a design. The purpose of the thread is to keep the point of the needle coated in ink, increasing the quantity of ink that penetrates the skin. Inks can be improvised from a number of sources such as coal, ashes or shoe polish, but Higgins "Black Magic" waterproof ink is the brand most commonly cited by collectors of so-called "India ink" or "stick and poke" tattoos in the United States[citation needed]. Sometimes called "prison tattoos", these tattoos are popular with gutter punks and others associated with the modern hobo subculture, who frequently tattoo visible parts of their bodies, including their hands and faces.

"Natural" tattoos

According to George Orwell, coal miners could develop characteristic tattoos owing to coal dust getting into wounds. This can also occur with substances like gunpowder. Similarly, a traumatic tattoo occurs when a substance such as asphalt is rubbed into a wound as the result of some kind of accident or trauma. These are particularly difficult to remove as they tend to be spread across several different layers of skin, and scarring or permanent discoloration is almost unavoidable depending on the location. In addition, tattooing of the gingiva from implantation of amalgam particles during dental filling placement and removal is possible and not uncommon. A common example of such accidental tattoos is the result of a deliberate or accidental stabbing with a pencil or pen, leaving graphite or ink beneath the skin.

Dyes and pigments

Early tattoo inks were obtained directly from nature and were extremely limited in pigment variety. Today, an almost unlimited number of colors and shades of tattoo ink are mass-produced and sold to parlors worldwide. Tattoo artists commonly mix these inks to create their own, unique pigments.

A wide range of dyes and pigments can be used in tattoos, from inorganic materials like titanium dioxide and iron oxides to carbon black, azo dyes, and acridine, quinoline, phthalocyanine and naphthol derivates, dyes made from ash, and other mixtures. The current trend for tattoo pigment favors Acrylonitrile butadiene styrene (ABS plastic) as seen by the widespread popularity of Intenze, Millennium and other ABS pigmented brands.

Iron oxide pigments are used in greater extent in cosmetic tattooing. Many pigments were found to be used in a survey of professional tattooists. Recently, a blacklight-reactive tattoo ink using PMMA microcapsules has surfaced. The technical name is BIOMETRIX System-1000, and is marketed under the name "Chameleon Tattoo Ink". This same ink can also be found as "The Original Blacklight Inks by NEWWEST Technologies".

Studio hygiene

The properly equipped tattoo studio will use biohazard containers for objects that have come into contact with blood or bodily fluids, sharps containers for old needles, and an autoclave for sterilizing tools. Certain jurisdictions also require studios by law to have a sink in the work area supplied with both hot and cold water.

Proper hygiene requires a body modification artist to wash his or her hands before starting to prepare a client for the stencil, between clients, and at any other time where cross contamination can occur. The use of single use disposable gloves is also mandatory. In some states and countries it is illegal to tattoo a minor even with parental consent, and it is usually not allowed to tattoo impaired persons, people with contraindicated skin conditions, those who are pregnant or nursing, those incapable of consent due to mental incapacity or those under the influence of alcohol or drugs.

Before the tattooing begins the client is asked to approve the final position of the applied stencil. After approval is given the artist will open new, sterile needle packages in front of the client, and always use new, sterile or sterile disposable instruments and supplies, and fresh ink for each session (loaded into disposable ink caps which are discarded after each client). Also, all areas which may be touched with contaminated gloves will be wrapped in clear plastic to prevent cross-contamination. Equipment that cannot be autoclaved (such as counter tops, machines, and furniture) will be wiped with an approved disinfectant.

Membership in professional organizations, or certificates of appreciation/achievement, generally helps artists to be aware of the latest trends. However, many of the most notable tattooists do not belong to any association. While specific requirements to become a tattooist vary between jurisdictions, many mandate only formal training in bloodborne pathogens, and cross contamination. The local department of health regulates tattoo studios in many jurisdictions.

For example, according to the health department in Oregon and Hawaii, tattoo artists in these states are required to take and pass a test ascertaining their knowledge of health and safety precautions, as well as the current state regulations. Performing a tattoo in Oregon state without a proper and current license or in an unlicensed facility is considered a felony offense. Tattooing was legalized in New York City, Massachusetts, and Oklahoma between 2002 and 2006.

Aftercare

Tattoo specific salves have become prevalent in recent years.

Tattoo artists, and people with tattoos, vary widely in their preferred methods of caring for new tattoos. Some artists recommend keeping a new tattoo wrapped for the first twenty-four hours, while others suggest removing temporary bandaging after two hours or less. Many tattooists advise against allowing too much contact with hot tub or pool water, or soaking in a tub for the first two weeks. This is to prevent the tattoo ink from washing out or fading due to over-hydration and avoid infection from exposure to bacteria and chlorine. In contrast, other artists suggest that a new tattoo be bathed in very hot water early and often.

General consensus for care advises against removing the scab that forms on a new tattoo, and avoiding exposing one's tattoo to the sun for extended periods; both of these can contribute to fading of the image. Furthermore, it is agreed that a new tattoo needs to be kept clean. Various products may be recommended for application to the skin, ranging from those intended for the treatment of cuts, burns and scrapes, to cocoa butter, salves, lanolin, A&D or Aquaphor. Oil based ointments are almost always recommended to be used in very thin layers due to their inability to evaporate and therefore over-hydrate the already perforated skin. In recent years, specific commercial products have been developed for tattoo aftercare. Although opinions about these products vary, there is near total agreement that either alone or in addition to some other product, soap and warm water work well to keep a tattoo clean and free from infection. Ultimately, the amount of ink that remains in the skin throughout the healing process determines, in large part, how robust the final tattoo will look. If a tattoo becomes infected (uncommon but possible if one neglects to properly clean their tattoo) or if the scab falls off too soon (e.g., if it absorbs too much water and sloughs off early or is picked or scraped off), then the ink will not be properly fixed in the skin and the final image will be negatively affected.

Tattoo removal

While tattoos are considered permanent, it is possible to remove them. Complete removal, however, may not be possible (although many doctors and laser practitioners make the claim that upwards of 95% removal is possible with the newest lasers, especially with black and darker colored inks), and the expense and pain of removing them typically will be greater than the expense and pain of applying them. Some jurisdictions will pay for the voluntary removal of gang tattoos. Pre-laser tattoo removal methods include dermabrasion, salabrasion (scrubbing the skin with salt), cryosurgery, and excision which is sometimes still used along with skin grafts for larger tattoos.

Tattoo removal is most commonly performed using lasers that react with the ink in the tattoo, and break it down. The broken-down ink is then absorbed by the body, mimicking the natural fading that time or sun exposure would create. This technique often requires many repeated visits to remove even a small tattoo, and may result in permanent scarring. The newer Q-switched lasers are said by the National Institute of Health to result in scarring only rarely, however, and are usually used only after a topical anesthetic has been applied. The NIH recognizes five types of tattoo; amateur, professional, cosmetic, medical, and traumatic (or natural). Areas with thin skin will be more likely to scar than thicker-skinned areas. There are several types of Q-switched lasers, and each is effective at removing a different range of the color spectrum. This laser effectively removes black, blue, purple and red tattoo pigment. New lasers like the Versapulse & Medlite laser treat these colors & yellow and green ink pigment, typically the hardest colors to remove. Black is the easiest color to remove.

Also worth considering is the fact that some of the pigments used (especially Yellow #7) are known to break down into toxic chemicals in the body when attacked by light. This is especially a concern if these tattoos are exposed to UV light or laser removal; the resulting degradation products end up migrating to the kidneys and liver. Laser removal of traumatic tattoos may similarly be complicated depending on the substance of the pigmenting material. In one reported instance, the use of a laser resulted in the ignition of embedded particles of firework debris.

Some wearers opt to cover an unwanted tattoo with a new tattoo. This is commonly known as a cover-up. An artfully done cover-up may render the old tattoo completely invisible, though this will depend largely on the size, style, colors and techniques used on the old tattoo. Some shops and artists use laser removal machines to break down and lighten undesired tattoos to make coverage with a new tattoo easier. Since tattoo ink is translucent, covering up a previous tattoo necessitates darker tones in the new tattoo to effectively hide the older, unwanted piece.