Here are some info I found..
How Many Treatment Sessions Will It Take To Remove The Pigment or Tattoo?
Depending on the type of pigment in your skin, it can be gone in as little as one to two sessions. When dealing with tattoos, the average, professional tattoo requires 6-8 treatments, while amateur tattoos require 3-4 treatments, all spaced approximately at least 8 weeks apart. The number of treatments depends on the amount and type of ink used, and the depth of the ink in the skin.
Do All Colors Of Ink Disappear Equally As Well?
No, dark (blue/black and green) and red inks fade the best. Purple may also respond. Yellow is very difficult to remove, although it may fade somewhat.
Is laser tattoo removal painful?
The heat produced by the laser procedure is localized to a very small area but it can cause some brief discomfort. For those with sensitive skin, a topical anesthetic can be used. Cooling ice packs are also used to reduce discomfort and swelling.