Richard Kelly a lighting expert from the 1950’s was honored with a retrospective at AIA chapter in Manhattan that I visited  again and again. I was intrigued by the scope of his work in the early days of electrical light. He worked side by side with many world renowned architects who were in the process of building their careers with our first NY skyscrapers: I.M. Pei, Mies van der Rohe, Louis Kahn and Phillip Johnson. Richard Kelly descriptively and with loads of adjective broke down 3 main types of lighting. 

Focal Glow Light focuses on a point or area. It “is the campfire…the limelight…the sunburst through the clouds…the pool of light at your favorite reading chair. Focal Glow separates the important from the unimportant, establishes precedence, can induce movement, control and direct traffic.” 

(Notes from lighting class with the lighting designer Hefferan at F.I.T. from the 1980’s).