One picture...multiple backgrounds?

[Nubster]

So the kids get home from school today and they have their school photo proofs with them. In years past there would generally be a pose or two in front of a generic colored background. This year, there are about 6-8 different backgrounds but it's the same photo in each. What I'm wondering, how is this achieved? I figure the post processing part is easy and pretty straight forward. But what background would be best to shoot the subject in front of? A green screen? White? Does it matter? I asked my son what the background looked like and he said it was blue but he really didn't remember. I have been contemplating buying various backgrounds to have on hand to do shots of the kids and family portraits at home but I'd much rather have one background and switch them up on the computer.

 

[Patrice]

The kids are posed in front of a green background screen and the image is then added in post. Your local weather girl is video-graphed the same way. That's why you are asked not to dress your kids in green on picture day.

 

[DustinB]

You just need a properly lit background with a solid color different from the subject to make compositing as easy as possible. They probably figured blue was the most likely to be different from the subject. As for how its done, that all depends on the software used. I prefer to use photoshop with a plugin called remask from topaz labs, but photoshop has decent tools for compositing.

A portrait background will be a lot easier to look convincing than say tryjng to match the lighting in a natural setting.