A lot of patients kept asking me why green ink was so difficult to remove with the ruby laser. At the time we didn’t know.
So I gathered a bunch of tattoo inks from Terry’s Tattoos in Glasgow and took them to the Chemistry Dept in Strathclyde University. I asked Prof Cruickshank if I could ‘borrow’ one of his lovely spectrophotometers to test these inks.
The results showed that green ink appeared to have ‘smaller’ molecules than the other colours! This may have been due to tighter molecular bonds in that particular ink.
This made sense since it means that higher energies would be required to break down those bonds. At the time I suggested the use of picosecond lasers, but these were not commercially available (until recently).
We wrote this report to explain our work. Prof Siomos wrote the paper since he was a proper chemist – I’m just a lowly physicist and view chemistry as one of the ‘dark arts’!!