Kelvin (K)

The unit used for measuring the colour temperature of light sources, named after the 19th-century physicist and engineer William Thomson, first Lord Kelvin (1824-1907). Average noon daylight usually has a colour temperature of around 5500K.

Key light

The main light on a subject used in studio photography.

Sources:  Pixabay, NASA,Wikipedia, Susan Wingfield Lamar High School

Sources:  Pixabay, NASA,Wikipedia, Susan Wingfield Lamar High School