Trying to decide on buying a Photosmart 375 printer, but have a question re\nthe ink. Hope there's some experts out there that can help me out. I\npresume the HP95 or HP97 Tri color ink cartridges have 3 seperate colors as\nthe name "Tri Color" implies. Do these cartridges contain a seperate Black\nink as well.? Or is black achived by mixing the 3 colors.?