IMPORTANT INFO HERE! We do a lot of artists the request that chroma key background, I think because they import into video software that has chroma key features. With that being said, if you are just doing photo work, you will avoid many extra steps if you shoot subject on a Light Gray Seamless Background. Keeping it neutral will eliminate the color cast spillover into the subject area.
Green Screen Series Video #6 This video shows how to use various techniques to composite and blend the Example #1 Green Screen extraction image into a different photo, changing day to night.