what is the black paint on football face

The black paint or grease that football players apply under their eyes is called eye black. It is used to reduce the glare from the sun and stadium lights, which can impede a players depth perception and ability to catch the ball as it flies through the air. Eye black is thought to work by absorbing the interfering light better than the natural skin tone can, reducing the glare for the player. It is not conclusively proven that eye black is effective in reducing glare. However, it is a common sight on the football field and is often used by players for aesthetic reasons as well. Eye black can be applied as a grease or synthetic sticker.