scarring, and amount of ink present. Effectiveness of the immune system may play a role as well. Complete laser tattoo removal requires numerous treatment sessions, typically spaced at eight weeks or more apart. Treating more frequently than eight weeks increases the risk of adverse effects and does not necessarily increase the rate of ink absorption. Anecdotal reports of treatments sessions at four weeks leads to more scarring and dyschromia and can be a source of liability for clinicians. At each session, some but not all of the tattoo pigment particles are effectively fragmented, and the body removes the smallest fragments over the course of several weeks or months. The result is that the tattoo is lightened over time. Remaining large particles of tattoo pigment are then targeted at subsequent treatment sessions, causing further lightening. Tattoos located on the extremities, such as the ankle, generally take longest. As tattoos fade clinicians may recommend that patients wait many months between treatments to facilitate ink resolution and minimize unwanted side effects. Certain colors have proved more difficult to remove than others. In particular, this occurs when treated with the wrong wavelength of laser light is used. Some have postulated that the reason for slow resolution of green ink in particular is due to its significantly smaller molecular size relative to the other colors. Consequently, green ink tattoos may require treatment with 755 nm light but may also respond to 694 nm, 650 nm and 1064 nm. Multiple wavelengths of light may be needed to remove colored inks. One small Greek study showed that the R20 method—four passes with the laser, twenty minutes apart—caused more breaking up of the ink than the conventional method without more scarring or adverse effects. However, this study was performed on a very small patient population (12 patients total), using the weakest of the QS lasers, the 755 nm Alexandrite laser. One of the other main problems with this study was the fact that more than half of the 18 tattoos removed were not professional and amateur tattoos are always easier to remove. Proof of concept studies are underway, but many laser experts advise against the R20 method using the more modern and powerful tattoo removal lasers available at most offices as an increase in adverse side effects including scarring and dyschromia is likely. Patients should inquire about the laser being used if the R20 treatment method is offered