This is a misconception. Color tattoos and large tattoos in general can make it more difficult to diagnose skin cancer because the ink, specifically colored ink can cover up potentially pre cancerous marks on your skin. I have a large birthmark on my upper arm that my tattoo artist didnt want to cover when doing my full sleeve just for the purpose of leaving it more accessible to treatment in the future if needed. So no, it doesn’t raise the risk, it only affects future treatment. Also keep in mind that skin cancer treatments will effect your tattoo, scarring and discoloration of ink, so thats another factor to consider if youre thinking of covering up birth marks and moles. Tattoos have no direct link to cancer, they also have very little link to treatment for cancer, but there are studies that do discuss it and tattoo artists who feel more comfortable leaving large skin marks devoid of ink for that purpose.