According to Mental Floss, tattooing over black ink with different colors is possible, and many people have done so to cover up unwanted or unfinished tattoos. White color is often used to cover up tattoos, but a number of darker colors are also used to cover black ink.
There are many other ways to cover up tattoos. For example, people often use laser treatments to remove unwanted body work, or they apply creams that lighten the lines of the tattoo. Laser treatment, however, can be painful and may cause damage to the skin.
People use tattoo-covering procedures to achieve different end results. Some people just want to change the color of their old tattoos, while others want to increase the contrast and depth of their tattoos. Some completely change the designs of their tattoos using these procedures.