What is "phot"

Etymology 1 n. A photometric unit of illuminance, or luminous flux through an area (symbol ph). Etymology 2

vb. (context informal English) to photograph#Verb

n. a unit of illumination equal to 1 lumen per square centimeter; 10,000 phots equal 1 lux

A phot (ph) is a photometric unit of illuminance, or luminous flux through an area. It is not an SI unit, but rather is associated with the older centimetre gram second system of units. The name was coined by André Blondel in 1921.

Metric equivalence:

$$1\ \mathrm{phot} = 1\ \frac{\mathrm{lumen}}{\mathrm{centimeter}^2} = 10,000\ \frac{\mathrm{lumens}}{\mathrm{meter}^2} = 10,000\ \mathrm{lux} = 10\ \mathrm{kilolux}$$

Metric dimensions: