system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why isn't there any skin colored tattoo ink that can be used to cover up bad tattoos?

Recently saw a picture of a woman who got a tattoo covered up by just getting a big black square tattoo over it. Why couldn't they do the same thing, but instead of using black ink, they use ink that matches her skin color?
gpt
Tattoo artist here.  Tattoo ink isn't actually "ink", it's pigment in a carrier (usually sterilized water and alcohol), which means that when it goes into the skin, it's staining the skin at a depth where the skin heals (anything above that dies and falls off during the scabbing process).  Have you ever stained white fabric black?  Now try staining that black with a lighter colour... doesn't really work.  Mostly because the darker colour will still show up through the lighter colour. 

*Edit*scabbing, not scanning.