Is our memory and subconscious color blind

I was watching 'The Practice', a TV show about criminal lawyers today and they showed a witness telling his story as he remembered it and through his eyes, they conveyed what happened. The whole flashback he had was in black and white. Which is when I realized that unless the flashbacks are a major part of the story, most often in movies or on TV, they are shown in black and white and so are dreams. Which brings the question to mind, why? I have no opinions but do have this doubt.