The ink has to be placed at the right level or will fade (too deep) or bleed (too shallow). As the ink particles stay on site they do become lighter over time (fade) as the body tries to remove them and breaks off little bits and pieces of color by sending cells to remove them. To remove tattoos, the best method is via laser treatments. Lasers emit light in a single wavelength. This wavelength is designed to interact with the colors of the tattoo. Unfortunately, there is no perfect wavelength that covers all pigments. Fortunately, the wavelengths used the most cover most of the colors. When the light is emitted onto the tattoo the color absorbs the light and the energy emitted causes the pigment granules to break into smaller pieces, which are then removed by the body and stored in lymph nodes. These systems almost never scar, but can. They also can cause a lightening of the skin due to removal of normal pigment. The number of treatments needed is dependent upon the type of ink as well as the age of the ink. Newer inks are being designed to be resistant to laser removal, as well as last longer without fading. “Jail house” or homemade tattoos (usually with ink from pens) are the easiest to remove. Red/orange or green colors are the hardest to remove with the most common laser systems. Blue or black are the easiest to remove no matter what system used. Pastel colors are easier than bold solid colors, and red/orange colors usually fade regardless of treatment. Lastly, the tattoo artist will sometimes mix colors to make new colors, which may compound the removal. Double tattoos (one covering another) are also hard to remove. The number of treatments depends upon the ink, but also upon how they are done. New data suggests multiple passes each session, which will increase the cost per session, but decrease the number of treatments, and hence to decrease the overall cost. The interval between treatments does not matter. One side effect of both getting a tattoo and removing it is ink allergy. This happens almost exclusively with red/yellow and orange colors. It usually happens within 2-4 weeks after the tattoo, sometimes after the second tattoo years later. There is a lumpy reaction in the skin that itches terribly (imagine poison ivy injected into the skin). It can also happen after laser treatments (even with no prior history), which is challenging as the ink is brought into the body and can cause a generalized rash instead of localized to the ink/tattoo. The primary therapy is topical steroids and /or intralesional steroid injections. It can be resolved with treatment. I would suggest a test spot of ink color in the area of the tattoo and wait a month or so before injecting a large area with color and or avoid red/yellow or orange colors. Medical/cosmetic tattoos use different inks, which sometimes can darken prior to being removed, which lengthens the number of treatments. White or flesh colors are the most common inks to do this. White inks with standard tattoos can also darken. In the USA (not in Europe) tattoo parlors are regulated and they must use sterile equipment, eliminating infections from contamination, which is still seen in Europe to this day. There are inks that have been developed that are easier to remove via laser, but will most likely fade faster as well.