Hi I'm trying to find this cartoon movie made in the 80s. Alli can remember is that the main character is a artist and that he gose to a world that's black and white and depressing and that when he starts to paint it turns the world colorful again. Also I know that he fights some kind of army too. Any ideas?

Maybe Coolworld with brad pitt ? I'm not sure

Found it it's the Elm Chanted Forest