What is in tattoo ink – and why is it important?

Why do we need to know what is in tattoo ink?

In general, it is always good for tattoo artists and their customers to know about the contents of tattoo ink. With regard to REACH, however, it is crucial. A certain level of knowledge about the contents of ink is needed in order to understand precisely why the REACH regulations are inherently problematic.

The framework of REACH was established to target something that is only of minor relevance with regard to tattoo ink, and REACH does not target what is crucial in relation to tattoo ink particularly well.

REACH has been put in the world to regulate dangerous substances. But the health problems that are most common in relation to tattoo ink do not necessarily come as a result of the substances that the inks are made of. Often the problem will lie with other issues, such as impurities or production processes that are not ideal. Impurities in substances are difficult to control, and banning the substances themselves is unlikely the best way to regulate them. Especially when the product in question is a complex mixture of many different substances.

The fact that tattoo ink is a complex mixture of many different substances is thus the reason why REACH is a cumbersome and ill-chosen framework for regulating tattoo ink, as it is only focusing on the substances and not the mixed compound and the ways in which they are produced. The new REACH regulation does deal with impurities to a certain extent. It does so by setting limits to impurities of substances in tattoo ink. This does to a certain extent handle the problem of impurities, but to our minds there could have been other and much better ways of regulating tattoo ink (read more about our suggestions here).

A brief overview of the contents of Tattoo ink

Tattoo ink is a mixture of four different kinds of substances:

• Pigments
• Binders
• Solvents
• Additives

Tattoo ink is made of a non-soluble pigment, a binder (that makes it soluble), a solvent (which gives it the liquid form), and additives.

Pigments

Pigments are the main ingredients in tattoo ink. Pigments are fine grained powdered substances that come in all kinds of colours. There are several different types of pigments, but the three main categories are carbon black pigments, inorganic pigments, and organic pigments. Furthermore, manufacturers can add fillers to pigments in order to enhance certain properties of the ink or to make storage easier.

All types of pigment have their advantages and drawbacks. They have very different qualities in terms of how they react when they are injected into the skin. Some are very bright, some have a tendency to fade with age, some are easily dispersed, some are easier to inject than others, etc.

They can all have different kinds of impurities such as heavy metals (in inorganic pigments and to a lesser extent in organic ones), aromatic amines (in organic pigments), and polycyclic aromatic hydrocarbons (in carbon black pigments). A large group of organic pigments, called azo-pigments, can degrade into potential cancerogenic chemicals such as benzedines – hence this entire group of pigments has been banned by the new REACH regulations.

In general, the point about pigments is that all of them have boths advantages and disadvantages. Many of the pigments can contain impurities in the form of unwanted substances that can potentially cause both allergies and even cancer. However, as the scientific literature states, these potential risks have led to comparatively few known real cases. Thus, for instance, as Dermatology Professor, Jørgen Serup has argued on several occasions, there is no evidence to suggest that getting a tattoo leads to an increase in the risk of getting cancer.¹

Binders

In order to make tattoo ink, which is a liquid compound, the insoluble pigments must be treated in a way that makes them soluble. That is the task of binders. The binder makes it easier to inject the ink into the skin.

The most commonly used binders in tattoo ink are:

• Polyethers
• Polyvinylpyrrolidone
• Block-copolymer
• Shellac

Binders are generally not viewed as biologically hazardous, especially because of their high molar mass, which gives them a low so-called bio-availability (meaning that they do not easily enter into the circulation of the body).

Solvents

A solvent is the liquid into which a pigment can be dissolved by the aid of a binder. All of the commonly used binders are soluble in water and hence the main ingredients in tattoo ink is usually water. Other solvents are also used, however, as they have different characteristics when it comes to drying properties, viscosity, and dispersibility – all of which play important roles for the practice of tattooing.

The most commonly used solvents are:

• Water
• Ethanol
• Isopropyl alcohol
• Glycerin
• Propylene glycol

Apart from water, these important solvents can irritate the skin in some way or other and should be limited in use (it should be noted however, that this has long been known among ink producers and that they have acted accordingly).

Additives

Additives are auxiliary materials that are added to inks in order to either protect from unwanted impurities or properties, or to promote certain wanted or necessary properties in the ink.

There are three particular kinds of additives that are important to mention:

• Surfactants
• Thickening agents
• Preservatives
• Surfactant (Surface-Active Additives (Tensides)): These are used in ink in order to stabilize the pigments during the production process. The finely grained pigments have a tendency to accumulate into larger structures that makes the binding and dissolving process more difficult. Surfactants make these processes smoother by ensuring that the pigment particles are covered completely by the binding solution.
• Thickening agents: These are used to hinder reagglomeration and sedimentation – or to put the point in more familiar terms, they are used to prevent inks from separating like a ruined hollandaise sauce. When inks are stored for a certain period of time, the pigment can potentially return to their solid state. Thickening agents are used to prevent this.
• Preservatives: These are used to hinder microbiological contamination. Because of the fact that tattoo inks are solutions of water, there is always a potential for microbiological contamination. Preservatives are added to hinder the reproduction of microorganisms in the ink. Using preservatives is not unproblematic, however, since they can give rise to allergic reactions.

To conclude

This brief overview hopefully provides a general albeit superficial introduction to the contents of tattoo ink. For more information we suggest taking a look at the articles and reports we are listing below. What should be clear from this overview of the contents of ink, however, is that precisely because tattoo ink consists of many different kinds of ingredients, regulations such as REACH, which focuses on individual substances risk missing the mark with regard to tattoo inks (for more on the way in which the REACH regulation works click here).

Literature
https://www2.mst.dk/udgiv/publications/2012/03/978-87-92779-87-8.pdf
https://www.karger.com/Article/Fulltext/369236
https://www.dr.dk/nyheder/viden/kroppen/du-aner-ikke-hvad-du-faar-ind-i-kroppen-meget-tatoveringsblaek-indeholder