paint (one) black
To make someone appear evil, malicious, or ill intentioned. He argued that the film was edited to paint him black, taking his statements out of context and mixing them with ominous music. Though he's been painted quite black by the media, in person he's actually a very pleasant guy.
Represent someone or something as evil or harmful. This idiom is most often used in a negative context, as in He's not so black as he's been painted. [Late 1500s]