Tattoo inks consist of pigments combined with a carrier, and are used in tattooing.
Tattoo inks are available in a range of colors that can be thinned or mixed together to produce other colors and shades. Most professional tattoo artists purchase inks pre-made (known as pre-dispersed inks), while some tattooers mix their own using a dry pigment and a carrier.
Tattoo ink is generally permanent. Tattoo removal is difficult, painful, and the degree of success depends on the materials used. Recently developed inks claim to be comparatively easy to remove. Unsubstantiated claims have been made that some inks fade over time, yielding a “semi-permanent tattoo.”
2 Pigment bases
4 Health concerns
5 Other tattoo inks
5.1 Glow in the dark ink and blacklight ink
5.2 Removable tattoo ink
5.3 Black henna
6 Ancient Roman recipe
In the United States, tattoo inks are subject to regulation by the U.S. Food and Drug Administration as cosmetics and color additives. This regulatory authority is, however, not generally exercised. The FDA and medical practitioners have noted that many ink pigments used in tattoos are “industrial strength colors suitable for printers’ ink or automobile paint.”
In California, Proposition 65 requires that Californians be warned before exposure to certain harmful chemicals; tattoo parlors in California must warn their patrons that tattoo inks contain heavy metals known to cause cancer, birth defects, and other reproductive harm.
Manufacturers are not required to reveal their ingredients or conduct trials, and recipes may be proprietary. Professional inks may be made from iron oxides (rust), metal salts, plastics. Homemade or traditional tattoo inks may be made from pen ink, soot, dirt, blood, or other ingredients.
Heavy metals used for colors include mercury (red); lead (yellow, green, white); cadmium (red, orange, yellow); nickel (black); zinc (yellow, white); chromium (green); cobalt (blue); aluminium (green, violet); titanium (white); copper (blue, green); iron (brown, red, black); and barium (white). Metal oxides used include ferrocyanide and ferricyanide (yellow, red, green, blue). Organic chemicals used include azo-chemicals (orange, brown, yellow, green, violet) and naptha-derived chemicals (red). Carbon (soot or ash) is also used for black. Other elements used as pigments include antimony, arsenic, beryllium, calcium, lithium, selenium, and sulphur.
Tattoo ink manufacturers typically blend the heavy metal pigments and/or use lightening agents (such as lead or titanium) to reduce production costs.
A carrier acts as a solvent for the pigment, to “carry” the pigment from the point of needle trauma to the surrounding dermis. Carriers keep the ink evenly mixed and free from pathogens, and aid application. The most typical solvent is ethyl alcohol or water, but denatured alcohols, methanol, rubbing alcohol, propylene glycol, and glycerine are also used. When an alcohol is used as part of the carrier base in tattoo ink or to disinfect the skin before application of the tattoo, it increases the skin’s permeability, helping to transport more chemicals into the bloodstream.
Main article: Tattoo medical issues
A variety of medical problems, though uncommon, can result from tattooing.
Medical workers have observed rare but severe medical complications from tattoo pigments in the body, and have noted that people acquiring tattoos rarely assess health risks prior to receiving their tattoos.
A recent case report also showed that tattoo pigments migrate into lymph nodes. These can show up on some types of medical scans as tumors. One woman was given a complete hysterectomy only to find out later that the lymph nodes contained tattoo pigment.
Other tattoo inks
Glow in the dark ink and blacklight ink
Both blacklight and glow in the dark inks have been used for tattooing. Glow in the dark ink absorbs and retains light, and then glows in darkened conditions by process of phosphorescence. Blacklight ink does not glow in the dark, but reacts to non-visible UV light, producing a visible glow by fluorescence. The resulting glow of both these inks is highly variable.
The safety of such inks for use on humans is widely debated in the tattoo community.
The ingredients in some “glow” inks are listed as: (PMMA) Polymethylmethacrylate 97.5% and microspheres of fluorescent dye 2.5% suspended in UV sterilized, distilled water.
Removable tattoo ink
Main article: InfinitInk
While tattoo ink is generally very painful and laborious to remove, tattoo removal being quite involved, a recently introduced ink has been developed to be easier to remove by laser treatments than traditional inks.
Health Canada has advised against the use of “black henna” temporary tattoo ink which contains para-phenylenediamine (PPD), an ingredient in hair dyes. Black henna is normally applied externally in temporary Mehandi applications, rather than being inserted beneath the skin in a permanent tattoo.
Another ink may be used instead of black henna. “Jagua”, a fruit based ink proven to be a healthier alternative to black henna.
Allergic reactions to PPD include rashes, contact dermatitis, itching, blisters, open sores, scarring and other potentially harmful effects.
Ancient Roman recipe
The Roman physician Aetius created a recipe for tattoo ink:
One pound of Egyptian pine bark
Two ounces of corroded bronze, ground with vinegar
Two ounces of gall (insect egg deposits)
One ounce of vitriol (iron sulphate)
Mix well and sift. Soak powder in 2 parts water and 1 part leek juice. Wash the skin to be tattooed with leek juice. Prick design with needles until blood is drawn. Rub in the ink
What happens when tattoo ink is injected into your skin? Most of it remains firmly lodged there, but some pigments travel to lymph nodes or even destinations in your body that are farther afield. All the while, you are left sporting a new tattoo.
From elaborate designs and sports team badges to the names of loved ones, tattoos come in all shapes and sizes. Their popularity has increased in the past 20 years, with 29 percent of the population of the United States reporting to have at least one tattoo.
But the inks used in tattoos are actually not developed for use in humans.
They are mostly made for other applications, such as the car paint or printing industries. The U.S. Food and Drug Administration (FDA) have, in fact, not approved any pigments for tattoos, and skin reactions to tattoos are not uncommon.
Although some tattoo inks are known to contain carcinogens, there is no concrete evidence that the chemicals in tattoo ink can cause cancer.
Solid needles are used to deposit ink into the deep layer of the skin. The body recognizes tattoo pigments as foreign particles and tries to clear them from the skin, but the chemistry of the ink used in tattoos makes this process quite difficult for the body. Hence, most of the color stays in the skin.
But why is it necessary to inject the ink so deeply?
Pigments are lodged in the dermis
The tattoo needle punctures your skin around 100 times per second, with the aim of depositing the ink in a region of 1.5 to 2 millimeters below the surface of the skin. The reason for this depth of penetration is to bypass the outer layer of the skin, or the epidermis.
This part of the skin constantly renews itself. Every day, thousands of epidermal cells are shed from your skin and replaced with new cells. Ink injected into the superficial skin layer would simply come off within 3 weeks.
In order to give the ink a permanent home in your body, the tattoo needle must travel through the epidermis into the deeper layer, or the dermis. Nerves and blood vessels are located here, which is why getting a tattoo hurts and your skin tends to bleed.
The bleeding is part of the skin’s natural defense against injury. The result is an influx of immune cells to the site of injury.
Macrophages are specialized immune cells, whose job it is to engulf foreign particles and clear them from the tissue. But this process is only partially successful when it comes to tattoo ink.
Some macrophages loaded with ink particles remain in the dermis, while other pigment particles are taken up by the main dermal residents, which are called fibroblasts. Clumps of pigment particles have also been found to stick between the dense collagen fibers of the dermis.
Although every new tattoo will display some pigment loss, the majority of the ink will stay in the skin. A study in mice reported that 42 days after tattooing, 68 percent of the dye was still located at the injection site.
But where is the rest of the ink?
Colorful lymph nodes, remote destinations
In most cases, macrophages carry the ink particles to the lymph nodes closest to the site of the tattoo. Because the cells cannot break down the particles, they become lodged there. The side effect is that the lymph nodes take on the same color as your tattoo.
There is also some evidence to suggest that tattoo ink particles can travel through the blood and become lodged in the liver.
So, next time you opt for a tattoo, remember that it might not just grace your skin; it may also impart your internal organs with a unique color display.