Does a journal retracting a paper also renounce copyright?
Good question. As far as I can tell, the answer is "no" and the journal retracting the paper still retains copyright (if it was given the copyright in the first place).

Here're some retraction policies: one, two, three. Although the question you ask is not discussed, two things can be noted:


Even if a paper is retracted, the publisher still distributes it (as in, it's still available from the journal's website). What changes is that the publisher makes it clear that the article is retracted.
The publisher only stops distributing the paper if they are legally obliged to do so (e.g. if the copyright is actually held by someone other than the authors, and the authors had no legal standing to sign the copyright to the publisher).


Since the publisher needs the copyright (or permission from the copyright holder) to distribute the paper, the logical answer is "no".