Brig. Gen. David E. Wood,  director of joint staff,

Brig. Gen. David E. Wood,  director of joint staff, Joint Force Headquarters, Pennsylvania National Guard, delivers the keynote address during the Major Octavius V. Catto Honor Ceremony in front of the Catto Monument, Philadelphia, Feb. 24, 2019. Catto was an African-American educator, civil rights activist and the highest-ranking African-American serving in the Pennsylvania National Guard at the time he was gunned down on Election Day 1871. (U.S. Air National Guard photo by Senior Airmen Timi Jones)

David Octavius Hill was a Scottish painter and photographer. He was a pioneer of photography in Scotland and is best known for his collaboration with Robert Adamson in which they produced some of the most important early photographs of Scotland.

In 1843, Hill was commissioned to paint a group portrait of the leaders of the Free Church of Scotland, which became known as the "Disruption Assembly" painting. He then decided to photograph the same people in order to have a more accurate representation of the individuals. This commission led him to take up photography and he teamed up with Robert Adamson, who was a master of the new collodion process. Together, they produced a large body of work that depicted the people and landscapes of Scotland during the mid-19th century. Their photographs are considered some of the most important early photographs of Scotland, and are widely recognized for their technical excellence and artistry.