Coloring black and white photographs is often a controversial process. Some argue that the original intent of the photographer was to have the image in black and white. Others suggest that photographers, back in the day of film, didn't always have on them the choice of black and white or color film at the moment they took their shot. Either way it is important to keep things looking natural. There have been some tragically comical examples of colorizing old film (just Google Wizard of Oz or Shirley Temple).