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