For some, knowing that one is making a permanent change to his or her body is part of the allure of getting a tattoo. For others, the suspicion that one might rue such a decision in more mature hindsight makes that irrevocability a deterrent. In recent years, the finality of the tattoo has been challenged by various removal schemes, but these have had drawbacks, including high expense, incomplete removal, scarring and the need for multiple treatments.Performance Indicator LLC, a Topsfield, Mass.-based company that specializes in a variety of color-change technologies, is developing a tattoo ink that disappears when activated by a laser. Robert Winskowicz, a managing partner of the company, explained that ink removal previously involved breaking up the dyes into particles that, when released into the body, could potentially cause a cancer risk. With his company’s ink, the tattoo will never break down or go away; the specialized materials will just become colorless when zapped by the right wavelength. The infrared laser light will be transparent to the skin and, hence, leave it unaffected.Other advantages are that the change is permanent and painless, leaves no visible traces and requires only one laser session. Is the next step to create an ink that could be turned on and off at will — say, off for the office and on for the beach? Winskowicz said that the idea is interesting, but that he doubts tattoo parlors would take kindly to it — they would want the customer to have to come back for more. The product, developed under license to dermatology specialist Freedom 2 Inc. of New York, is slated for release later this year. Meanwhile, squeamish parents had better start thinking up new arguments to deter their offspring from body art. “Someday you’ll regret it” will no longer suffice.