Between 1965 and 1978, as part of their regularly issued series the Postal Service issued the Prominent Americans series. You can probably guess the faces on the stamps based on the name of the series: famous Americans like Thomas Jefferson, Frank Lloyd Wright, Albert Einstein, and John F. Kennedy are just a few examples of the well-known figures featured on the stamps.
The Prominent Americans Series came after the Liberty issue which featured prominent patriotic figures and locations. The Americans Series emerged from a desire for more modernity in stamp options.
Despite being one series, the stamps had a number of different font and image styles to keep things fresh.
The series was not without its own complications: the 5 cent Washington stamp had more shading than necessary on his face, making it look unshaven or dirty. Later issues of Washington had a lighter, cleaned up face.
But despite that the series was popular in emphasizing patriotic, American themes in the world of philately. Looking at each individual stamp emphasizes the individuality of each important character in American history…Even if that individuality meant having an unshaven face.