It's Cracked, but one of their truth-filled articles. Must be old research, though, because there's no mention of the damage the heavy metals do to the lymph system. The colorful ones are probably like eating lead paint.
Also, they didn't talk about the spread of diseases such as Hepatitis, among others, by getting tattoos, which is very common.
Like the article points out, getting a tattoo is a medical procedure. Most of the shops I have seen are very, very, far from being sanitary. Unless they are sterilizing all of the equipment after each patient, getting a tattoo is like sharing a needle in a drug house.
