title: In vitro spectral analysis of tattoo pigments.
abstract: BACKGROUND
  Absorption spectra of common tattoo pigments, their reaction to irradiation at 532 and 752 nm, and correlation with their titanium and iron component are important to the selection of an optimal laser device.
  
  
  OBJECTIVE
  The objectives were (1) to establish the absorption spectra of common tattoo pigments and India ink and (2) to determine their response to laser irradiation at 532 and 752 nm and correlate this to their composition.
  
  
  METHODS
  Samples of 28 tattoo pigments and India ink were mixed in agar and analyzed with a spectrophotometer. These agar plates were irradiated with Q-switched wavelengths of 532 and 752 nm.
  
  
  RESULTS
  The highest absorbance of red was in the complementary spectrum, while blue, yellow, and orange had peaks in the adjacent portion of the visible light spectrum. There is great variability in the absorbance of green tattoo material. Pigment darkening was noted at both wavelengths in all iron-containing pigments except black. It was variable in those containing titanium. Pigments tested responded with either clearance or darkening at 532 nm; however, response at 752 nm was more limited.
  
  
  CONCLUSIONS
  (1) Tattoo pigment absorption spectra can explain why some colors are more resistant to removal. (2) Pigment darkening is a complex process.
authors.affiliation: Naval Medical Center San Diego, California 92134, USA. trisha.beute@med.navy.mil
authors.forename: Trisha Clarke
authors.initials: TC
authors.lastname: Beute
authors.forename: Charles H
authors.initials: CH
authors.lastname: Miller
authors.forename: Anthony Louis
authors.initials: AL
authors.lastname: Timko
authors.forename: Edward Victor
authors.initials: EV
authors.lastname: Ross
mesh_terms: D002244:Carbon / Q000737:chemistry / Q000528:radiation effects; D004396:Coloring Agents / Q000737:chemistry* / Q000528:radiation effects*; D006801:Humans; D066298:In Vitro Techniques; D007501:Iron / Q000032:analysis; D007834:Lasers; D013053:Spectrophotometry; D013653:Tattooing; D014025:Titanium / Q000032:analysis; D014481:United States
chemical_list: D004396:Coloring Agents; C028433:chinese ink; C009495:titanium dioxide; D002244:Carbon; D014025:Titanium; D007501:Iron