In vitro spectral analysis of tattoo pigments.
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.
Beute
Trisha Clarke
TC
Naval Medical Center San Diego, California 92134, USA. trisha.beute@med.navy.mil
Miller
Charles H
CH
Timko
Anthony Louis
AL
Ross
Edward Victor
EV
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
D004396:Coloring Agents; C028433:chinese ink; C009495:titanium dioxide; D002244:Carbon; D014025:Titanium; D007501:Iron