Page 117 - Blog Posts v1

Red absorbs most strongly below 600nm – where the frequency-double Nd:YAG line is at 532nm. But it is a very poor absorbed above 700nm melanin that the ruby, alexandrite and fundamental Nd:YAG wavelengths will not be well absorbed.
Finally, yellow has low absorption for all the standard laser wavelengths since its peak absorption is down near 500nm. The YAG wavelength, 532nm, is the best option for yellow, but even this is only marginally better than the other wavelengths.
I nicked that above image off the internet. It’s quite nice but a bit inaccurate. It’s not as simple as this image portrays...
Important points:
Firstly, it is impossible to know which coloured inks are actually present in any tattoo. Our eyes can easily deceive us. Most tattoo artists mix a number of ink colours to attain their desired final colour. When this mixture is hit by a laser wavelength, the constituent colours will absorb different amounts of energy, depending on their individual absorption coefficients. Consequently, the reactions will vary between these colours and hence the fading will probably differ too.
Secondly, changing wavelengths is more than simply changing the colour of the light. For example, 532nm is strongly absorbed in melanin and haemoglobin meaning that the
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