The process of tattooing has changed very little over time. Coloured pigments are inserted under the skin using a sharp object or needle, forming a design. The chemistry of tattoo inks varies, since inks are not usually regulated and can contain any number of chemicals for pigment. When you are looking to be tattooed, understanding the contents of the ink can help prevent an allergic reaction.
Brown, Tan and Black Ink
Ochre, a compound consisting of clay and ferric oxides, is a common ingredient in brown, tan and flesh-toned inks. Deep browns are created by using fired ochres, which are heated to remove additional moisture and give a deeper colour.
Black ink is a staple of tattooing and there are many combinations of chemicals used for this pigment. Iron oxide was once a common ingredient in black ink, but certain states such as California have been outlawing the use of heavy metals in tattoo inks. Modern black inks contain carbon or logwood to produce heavy black tones.
Violet, Green and Blue
Violet inks are created from manganese or quinacridone. The problem with many violet inks is a tendency to fade with exposure to sunlight, causing discolouration and requiring additional touch-ups.
Ingredients for green inks include Prussian blue, chromium oxide, lead chromate, malachite and ferrocyanides.
Blue inks are created from a variety of chemicals. Potential ingredients include lapis lazuli, cobalt and azure blues. One of the most common blue pigments is created using copper salts. This compound is FDA approved for use in baby furniture, toys and contact lenses.
Yellow, Red and Orange
Turmeric, a common kitchen spice, is often used as a colouring for yellow inks. Other yellow options include ochre, cadmium yellow, disazodiarylide, curcuma yellow or chrome yellow.
Red inks can include ingredients such as cadmium red, iron oxide (rust), and napthol or cinnabar are all used as red tattoo pigment. These ingredients may be associated with a common allergic reaction, sometimes called "red reaction," which causes the tattoo to become sore and inflamed.
Orange pigments are quite colour-fast and are stable, structured chemicals. This ink's potential ingredients include disazodiarylide, cadmium seleno-sulphide and disazopyrazolone.
Tattoo inks contain a carrier, which is used to suspend the pigment. Modern inks use substances which are nonreactive such as glycerine, witch hazel, ethyl alcohol or pure distilled water.