Page 52 - An Introduction to Laser Tattoo Removal

Chapter 2 – Fundamentals of Laser Tattoo Removal v1.0
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Strong – can lead to hyperpigmentation
Weak – slight chance of bruising
Strong – deeper penetration than 532nm
755
Strong – can lead to hyperpigmentation
Weak – slight chance of bruising
Strong – deeper penetration than 532nm or 694nm
1064
Weak – very little interaction with melanin means less epidermal damage and low change of hyperpigmentation
Very weak – very little chance of bruising
Moderate – deepest penetration of these wavelengths
(Mike wrote an article, published in the British Journal of Dermatology, on the absorption of 532nm in blood – view here).
As for absorption by coloured inks.... Well, that depends entirely on the constituents within the ink. It is impossible to predict, with any real certainty, how strongly any wavelength will be absorbed by any coloured ink! This can only be determined by testing.
Figure 26: In this tattoo, some of the ink colours reacted well to the laser energy (QS, 1064nm). However, the small patches of red and yellow don’t appear to have reacted at all, while the lighter blue portions have not reacted (probably due to high levels of titanium dioxide).
This is fairly typical in many multi- coloured tattoos. Different colours react differently to laser energy, simply because of the constituent inks. We can never know what is actually in those colours, only what we perceive! Watch this animation for an explanation.
The above figure shows a black/red/yellow tattoo being treated with a 1064nm wavelength from an Nd:YAG laser. You can see that the black ink reacts very clearly but the red and yellow do not. The black ink is strongly absorbing the laser energy and generating steam bubbles which are clearly visible. But the red and yellow inks are not absorbing sufficient energy from this wavelength to create those steam bubbles – which is why those colours look unchanged! ________________________________________________________________________ 52
Chapter 2 LEVEL A Laser Tattoo Removal
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