Help with video editing

[Tjarboe]

Hello everyone.

I'm going to start off looking for answer here since we have so many people who are very knowledgable on so many different subjects.

I have some videos that I would like to edit.  I've been using iMovie for Mac, but have not figured this out yet.

What I'm trying to do is to turn a video black and white, this is easy, however, I want to make the subject of the video, in this case my son, color.  What is the easiest way to do this?  I'm guessing, since I've never done this before, that I would have to use layers?  Does anyone know if iMovie supports this?

Thanks to any help.