A user cannot make a film black and white without the consent of the rights holder. That would be an infringement of the exclusive rights of the author (Art. 11 Para 1 CopA, Art. 10 Para. 1 (d) CopA). This act would lead to the risk of being taken to court for breaching Art. 67 Para. 1 (c) CopA, which carries a custodial sentence not exceeding one year or a monetary penalty.
This may also overlap with civil actions (e.g. an action for damages).