Leather panels are typically tanned to a natural brown color, which is usually required in professional leagues and collegiate play. At least one manufacturer uses leather that has been tanned to provide a "tacky" grip in dry or wet conditions. Historically, white footballs have been used in games played at night so that the ball can be seen more easily however, improved artificial lighting conditions have made this no longer necessary. At most levels of play (but not, notably, the NFL), white stripes are painted on each end of the ball, halfway around the circumference, to improve nighttime visibility and also to differentiate the college football from the pro football. However, the NFL once explored the usage of white-striped footballs – in Super Bowl VIII.