Spectrum 3415F User Manual page 3

A quantum is the amount of energy possessed by a photon.
Photosynthesis is driven primarily by light in the range be-
tween 400 and 700 nanometers, which is referred to as Photo-
synthetically Active Radiation, or PAR light. The intensity of
PAR light is referred to as Photosynthetic Photon Flux Den-
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sity (PPFD), which is measured in units of µmol m s (the
number of photons in units of micromoles, striking an area
one meter square each second). Quantum Light Meters are
calibrated to display PPFD. The meters display PPFD in the
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range 0-1999 µmol m s .
Field Scout Quantum Light Meters are calibrated for sunlight.
Due to differences in the spectrum generated by artificial
lights, the following adjustments must be made in the value
shown on a sunlight-calibrated meter:
Fluorescent: reads 8% high, so multiply the display by 0.92.
Metal Halide: reads 6% high, so multiply the display by 0.94.
High Pressure Sodium: 0% error—no adjustment needed.
Sunlight: 0% error—no adjustment needed.
Note that the 3415FSE meter displays accurate readings for
fluorescent lights when set to "Electric".
The chart below displays the spectral response of the Quan-
tum Light Meters.
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