Phot
Unit systemCGS units
Unit ofIlluminance
Symbolph
Conversions
1 ph in ...... is equal to ...
SI derived unit   10000 lx
SAE units   929 fc

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.[1]

Metric equivalence:

${\displaystyle 1\ \mathrm {phot} =1\ {\frac {\mathrm {lumen} }{\mathrm {centimetre} ^{2))}=10,000\ {\frac {\mathrm {lumens} }{\mathrm {metre} ^{2))}=10,000\ \mathrm {lux} =10\ \mathrm {kilolux} }$

Metric dimensions:

Illuminance = luminous intensity × solid angle / length2