Dyes commonly used in tattooing are: 

• Black color: India Ink (MC used); China Ink, Soot 
• Blue: Prussian blue (ferric ferrocyanide); Cobalt, Indigo, Ultramarine 
• Green: Chromic oxide 
• Red: Cinnabar, vermillion 
• Brown: Ochre 

Methods to make tattoo readily visible are: 

• Infrared photography 
• Ultraviolet light 
• Rubbing the part and examining under magnifying glass 
• Treating with hydrogen peroxide and 0.5% caustic potash 
• Histological examination of regional lymph nodes may show tattoo pigment deposition.