“Football” Sports Art
Here’s some information about a football much of which I did not know before reading about it on Wikipedia http://en.wikipedia.org/wiki/Football_(ball%20#American_and_Canadian_football. The football is also referred to as a "pigskin", because of their early use of pig's bladder to cover the ball.The ball is about 11 inches (28 cm) long and about 22 inches (56 cm) The exterior of the ball is made of leather, which is required in the NFL and collegiate football. The leather is usually stamped with a pebble-grain texture to help players grip the ball. Four panels or pieces of leather are required for each football.
Two of the panels are perforated along adjoining edges, so that they can be laced together. One of these lacing panels receives an additional perforation and reinforcements in its center, to hold the inflation valve. Each panel is attached to an interior lining. The four panels are then stitched together in an "inside-out" manner. The edges with the lacing holes, however, are not stitched together. The ball is then turned right side out by pushing the panels through the lacing hole.A polyurethane or rubber lining called a bladder is then inserted through the lacing hole. Leather laces are inserted through the perforations, to provide a grip for holding, hiking and passing the football. Before play, the ball is inflated to an air pressure of 12.5–13.5 psi.