What's Actually in Tattoo Ink? Pigments, Carriers and Additives
A tattoo ink starts with pigment suspended in liquid. Additives help the mixture stay usable, and residues can arrive with the raw materials. The broad categories are familiar; the exact ingredients and proportions vary between brands and colors.
Formulating ink made me pay more attention to what fills each of those roles.
Pigment: the part that stays
Pigment is solid particles, not dye. Dye dissolves; pigment does not. That distinction is the whole reason a tattoo is permanent. The particles sit in the dermis where immune cells hold them in place, rather than washing out the way a dissolved colorant would.
Pigments fall into two broad families.
The inorganic group includes carbon black, titanium dioxide and iron oxides.
Carbon black, CI 77266, is the basis of most black inks. Its roughly 10 to 100 nanometer particles form clusters. Titanium dioxide, CI 77891, provides white and lightens mixed shades; its anatase and rutile crystal forms behave differently.
Iron oxides use CI 77491, 77492 and 77499 for reds, yellows and black, with mixtures giving browns. They are common in permanent makeup.
Organic pigments are carbon-based compounds that provide much of the color range.
Azo pigments cover many reds, oranges and yellows. Quinacridones such as PR122, PV19 and PR202 provide magentas and violets. The copper phthalocyanines, including the PB15 family, PG7 and PG36, provide blues and greens.
Pigments are identified by Color Index number. CI 77266 is carbon black; CI 74160 is phthalocyanine blue. Those numbers are the only precise way to say what a color is made of, which is why a label without them tells you very little.
Carrier: the part that moves
The carrier suspends the pigment and helps control flow off the needle.
Purified water is the base of many inks. Witch hazel can contribute to flow, glycerin adds viscosity and slows drying, and alcohol changes fluid behavior while inhibiting some microbial growth. Glycols appear in some formulations too, as solvents, humectants or parts of the dispersion system. Their presence doesn't replace sterility testing.
Carrier ratio is most of what separates a lining black from a grey wash. Same pigment, different liquid, completely different behavior in the skin.
Additives: the part nobody lists
The less visible part of the formula is the dispersion package, along with preservatives and material carried over from pigment manufacturing.
Dispersants and surfactants help keep particles from re-clumping. Their selection and ratios are often proprietary. Some formulations include preservatives, while manufacturing residues such as rosin oxidation products or PAHs may arrive with the pigment rather than being intentionally added.
What changes by color
With blacks, much of the difference is carbon-black grade, pigment load and dispersion. Whites and pastels usually bring titanium dioxide into the mixture, which also affects needle wear.
Red shades often use azo or quinacridone pigments and appear prominently in clinical reports of allergic reactions. Blues and greens commonly use copper phthalocyanines, so blue doesn't automatically mean a cobalt pigment.
Why the bottle is only a starting point
Knowing the three components does not mean you know what is in a specific bottle, because labels are frequently incomplete. Analytical surveys on both sides of the Atlantic have found undeclared pigments and additives in a majority of inks tested, and ingredients listed that were not actually present.
That is a problem worth understanding on its own terms, including what the law does and does not require manufacturers to disclose. I cover it in why you can't just read the label.
For how the pigments themselves behave once they are in skin, including particle size, metals and light exposure, see do tattoo ink ingredients interact? For black specifically, see black tattoo ink explained.
Why a test spot cannot clear an ink as safe
A small trial tattoo can't tell you that the ingredients will be safe over time. A quiet patch only tells you there was no obvious reaction there during the time you watched it. Reactions can appear months or years later, and pigment can change in skin or under light. Even dermatologist-supervised patch testing has limits for tattoo-pigment allergy.
If you've had a serious allergy or a previous tattoo reaction, discuss it with a dermatologist rather than implanting more material to see what happens. Schubert, Kluger and Schreiver (2023), review of tattoo hypersensitivity and patch testing.
Sources
Wang et al. (2021), "Analytical survey of tattoo inks," Contact Dermatitis 85(3):340-353
FDA: Tattoos & Permanent Makeup Fact Sheet
This is an educational overview, not medical advice. If you have a persistent or worsening reaction to a tattoo, have it assessed by a qualified clinician.
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