Empress Sissi of Austria wore an anchor on her shoulder, the famous Ice Age man Ötzi had - over 5000 years ago -more than 61 different marks on his skin, and with some professional footballers you get the feeling they spend more time in a tattoo studio than on the football field. Tattoos have become fashionable and are a popular form of body art - and have a lot to do with chemistry!
The country with the most tattooed people is Italy (48%) followed by Sweden (47%) and USA (46%). Much fewer are in Israel (25%), Turkey (30%) or Mexico (32%). The aesthetic appeal of tattoos is certainly debatable, but it is undeniable that a tattoo is a decision for life. Because once placed under the skin, it ideally lasts a lifetime. What long-term effects the colour pigments have on the body can hardly be assessed at present, as there are no representative clinical and dermatological studies.
Tattoo inks are a mix of several chemicals. Inorganic pigments made of carbon black and titanium white are used as tattoo colours, sometimes iron oxides are used for yellow or red colour components. Due to the natural nickel content, however, this can cause allergies, so these colours are on the retreat. Today, organic pigments are mainly responsible for the colour splendour on the skin.
But what characterises a good tattoo ink? First and foremost, it must be a pigment colour that does not dissolve, is encapsulated by the skin on the spot and remains there. It must be light-stable so that it does not fade over time. Ideally, it is a non-Newtonian fluid that is solid or liquid depending on shear forces. This property is important when applying the ink under the skin. The art of tattooing begins with the first needle prick. Today, modern fine-needle tattoo machines are used to insert the colours up to two millimetres under the skin with high stitch frequency - without anaesthesia, because even trained tattoo artists are not allowed to anaesthetise. When the needle is inserted into the skin, the ink, which is initially thick, can flow easily into the skin layer under pressure. When the needle is removed, the ink becomes thick again and no longer runs. When the inserted colour comes to rest, the micro-fine colour pigments must not clump or coagulate. Tattoos are always a health hazard: they can cause allergic reactions, chronic inflammation, and even permanent photosensitivity, although classic tattoos with carbon or titanium dioxide pigments are generally the most tolerable.
Ultimately, it is everyone's own decision to get a tattoo. As beautiful and meaningful as tattoos can be. However, anyone who undergoes such a procedure should be aware that the colour chemistry literally goes under the skin for a lifetime and the risks are incalculable - so "Think before you ink."