Tattoo marks are designs made in the skin by multiple small puncture wounds with needles or an electric vibrator dipped in coloring matter. The dyes commonly used are Indian ink, carbon (black), cinnabar or vermilion (mercuric sulphide) red, chromic acid (green), indigo, cobalt, prussian blue (ferric ferrocyanide), ultramarine (blue). Techniques and dyes vary from country to country.
The most permanent pictures are made when the dye penetrates the dermis. If the dye is deposited into deeper layers of dermis, it will be removed by phagocytes. Most of the tattoo marks are found on the arms, forearms and chest, but may be present on any part of the body. If the pigment has been deposited below the epidermis, it will very slowly become fainter and certain pigments, such as vermilion, and ultramarine may disappear after about ten years.
The rate of fading depends not only on the composition of the pigment, but also on the depth to which it penetrates the skin, and the site which is tattooed. Parts protected by clothing retain the design for longer period than the exposed parts of the body. Tattoos on the hands disappear early due to constant friction.
A faded tattoo mark becomes visible by the use of ultraviolet lamp or rubbing the part and examining with magnifying lens. Infrared photography makes old ones readily visible. The tattoo marks are recognized even in decomposed bodies when the epidermis is removed. Lymph nodes near a tattoo mark show a deposit of a pigment. The color, design, size and situation of tattoo marks should be noted. Drawing or photography is more useful.
Sydney Shark Case
James Smith disappeared on April 8, 1935. A shark was caught alive 14 days later, which vomited a human arm at the aquarium where it was kept. Medical examination revealed that the arm was severed from a dead body by a sharp weapon. Smith’s wife and brother identified the arm from the marks of two men boxing. The identity was also confirmed by fingerprints. Later, Patric, Brady was tried for his murder at Sydney.
Septic inflammation, erysipelas, abscess, gangrene, syphilis, AIDS, leprosy and tuberculosis may occur.
Erasure of tattoo marks
(1) SURGICAL METHODS: (a) Complete excision and skin grafting, (b) production of burn by means of red hot iron, (c) scarification, and (d) carbon dioxide snow.
(3) CAUSTIC SUBSTANCES remove pigment by producing inflammatory reaction and a superficial scar, e.g., mixture of papain in glycerine, zinc chloride and tannic acid.
(4) LASER BEAM: By exposure to laser beams, the particles of the dye get vaporized and expelled from the tissues in gaseous form.
(5) Confluent smallpox and sometimes chronic eczema in children can obliterate tattoo marks.
Tattoo marks is useful in
(1) identity. If there are large number of tattoos, positive identification can be made by them alone. Initials and dates, regimental or nautical details, identity numerals, one’s own name, etc., provide more scientific basis for identification.
(3) God of worship.
(4) Indicate culture or life-style.
(5) The distribution of tattooing and the nature of designs and figures may indicate a particular country or region.
(6) The presence of indecent figures points to definite perversion in the individual.
(7) They reflect travel, history, war, occupation, sex interest, etc.
(8) Gang members may wear tattoo marks of allegiance and symbolism to indicate status or other aspects relevant to their particular group.
(9) Illicit drug users may have them that identify them as belonging to a particular group or to obscure injection sites.