Dark and tanned skin absorbs the laser light in the same manner as the tattoo, creating less ideal results. Tattoos on the upper part of the body tend to respond better to laser removal than tattoos below the knees. Other types of accidental tattoos that show good results from laser are those from gunshots, pencil leads, paint, and severe nicotine stains on the fingers. Sunspots respond very well to the tattoo lasers also. It is important to note that lasers do not cause cancer.
Most lasers are less harmful than sunlight.
Lightening is caused by destruction of the normal pigment in the skin. Darkening of certain light ink colors such as white and beige can frequently occur. Tattoo artists often use these colors in attempting to cover up an unwanted tattoo. Because these light colors can permanently turn quite dark or even black, they are tested before full treatment is given. Some colors are impossible to remove completely, even with several treatments from both types of tattoo lasers.