ah, HERE'S how to get those crisp paint lines - great trick! Then I of course used my favorite trick to have crisp lines - paint over the sticker with Mod Podge. If anything seeps, it will be the clear mod podge, not the paint color.
Looking to add custom posters to your classroom? Just pick a template, type in a quote, and you're done! Thinking this would work good for our new 4 school wide rules! Create a poster and print at CopyMax.