What is lux?
Lux is the SI unit of illuminance, measuring luminous flux received per unit area. It is the standard unit for evaluating lighting conditions in workplaces, photography studios, building codes, and health and safety standards.
What is phot?
A phot is a CGS system illuminance unit equal to 10,000 lux. It is now largely obsolete but may be encountered in older scientific literature and historical photometric measurements.