The deposition into skin of inert materials that produce colored effects may be accidental or premeditated. The usual material that enters the skin accidentally is carbon from mischance, such as fire blast, abrasion on dirty surfaces, and stabs of sharp pencils. Figure 25-14 shows a stripe of blue color resulting from an incised wound incurred in a fall on a tarred pavement. Figure 25-15 is a conventional tattoo placed by a tattoo artist. The pigments used by tattooists to produce colors are carbon for blue and black, cinnabar or cochineal for red, cadmium salts for yellow, and cobalt salts for green. These materials are inert, but on occasion granulomas (Fig. 25-15) develop, especially from cinnabar. The color produced by carbon is black if placed superficially and progressively dark to light blue the deeper it is placed. The use of lasers for removal can be quite successful.