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 CONVERSION:  PPF TO LUX
NOTE: The conversion from PPF (µmol m-2 s-1) to Lux varies under different light sources. For a complete discussion please see the reference listed below.
 CONVERSION FACTORS
 
 
PPF (µmol m-2 s-1) TO LUX
Sunlight
54
Cool White Fluorescent Lamps
74
High Pressure Sodium Lamps
82
High Pressure Metal Halide Lamps
71
     
LUX TO PPF (µmol m-2 s-1)
Sunlight
0.0185
Cool White Fluorescent Lamps
0.0135
High Pressure Sodium Lamps
0.0122
High Pressure Metal Halide Lamps
0.0141
 
 

Multiply the PPF by the conversion factor to get Lux. For example, full sunlight is 2000 µmol m-2 s-1 or 108,000 Lux (2000 * 54).
    

Multiply the Lux by the conversion factor to get PPF. For example, full sunlight is 108,000 Lux or 2000 µmol m-2 s-1 or (108,000 * 0.0185).
  
 PPF TO LUX REFERENCE TABLE
 
PPF
(µmol m-2 s-1)
  10
100
200
300
600
1000 
2000 
 
LUX
(SUNLIGHT) 
  540
5,400
10,800  
16,200  
32,400  
54,000  
108,000   
 
LUX
(HPS) 
  820
8,200
16,400  
24,600  
49,200  
82,000  
  164,000    
 
LUX
(METAL HALIDE) 
   710
7,100
  14,200  
  21,300  
  42,600  
  71,000  
   142,000    
 
LUX
(FLUORESCENT)   
   740
7,400
14,800 
22,200 
44,400 
74,000 
148,000   

 

 
 DEFINITIONS
 PHOTOMETRIC UNITS, ILLUMINANCE:
 
FOOT-CANDLE = one lumen per square foot.  The 16th General Conference on Weights an Measures (CGPM), Oct. 1979, decided that the candela is the luminous intensity of a source emitting monochromatic radiation of frequency 540 x 1012 Hz and radiant intensity 1/683 watt per steradian.  This corresponds to 683 lumens per watt of radiation at approximately 555 nm wavelength, which is near the maximum of the standard photopic spectral luminous efficiency curve.

LUX = one lumen per square meter; differs from foot-candle by about a factor of 10.
 QUANTUM UNITS, PHOTON FLUX DENSITY:
 
MICROEINSTEIN per second and square meter  (µE m-2 s-1).  The einstein has been used to represent the quantity of radiant energy in Avogadro's number of photons and also Avogadro's number of photons.  The second definition has the einstein equal a mole of photons. While commonly used as a unit for photosynthetically active radiation (PAR), the einstein is not an SI unit.

MICROMOLE per second and square meter (µmol m-2 s-1).  This term is based on the number of photons in a certain waveband incident per unit time (s) on a unit area (m2) divided by the Avogadro constant (6.022 x 1023 mol-1).  It is used commonly to describe PAR in the 400-700 nm waveband.
DEFINITIONS FROM:
 
Thimijan, Richard W., and Royal D. Heins. 1982. Photometric, Radiometric, and Quantum Light Units of Measure:  A Review of Procedures for Interconversion. HortScience 18:818-822.