Doc420
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400w
1. Philips Agro 400w 230v 660 uMol (output stabile, extra blue spectrum)
2. Philips Greenpower 400w 230v 725 uMol (output stabile)
600w
1. Philips SON-T plus 600w 230v 1045 uMol (output "instabile") output degrades fast
2. Philips SON-T Greenpower 600w 230v 1100 uMol (output stabile)
3. Philips SON-T Greenpower 600w 400v 1150 uMol (output stabile)
4. Philips SON-T Greenpower 600w 400v EL* 1170 uMol (output stabile) *specialy for high frequency electronic ballast >100.000 hertz
1000w
1. Philips SON-T Greenpower 1000w 400v EL* DE 1925 uMol (output stabile) in reality the lamp gives 2100 uMol at the start of its lifetime.
*specialy for high frequency electronic ballast <100.000 hertz
The standard measurements of light output have traditionally been done through the foot-candle, lumens and lux. They quantify how humans experience the intensity of light, based on the limited sensitivity of the human eye in the yellow/green area of the spectrum (around 550 nm). Plants however use a much wider spectrum for photosynthesis, called the PAR spectrum (Photo-synthetically Active Radiation), ranging from 400-700 nm
Human eye sensitivity versus plant sensitivity
Photosynthesis is not driven by brightness of the light according to the human eye or the energy of a photon (which varies for different colors) but purely by the number of photons in the PAR spectrum. You need about eight photons to bind one CO2 molecule. So to quantify potential photosynthesis it is all about the number of photons within the PAR spectrum hitting the plant. This is expressed as Photosynthetic Photon Flux (PPF – total photons emitted from a light source per second) and Photosynthetic Photon Flux Density (PPFD – the number of photons hitting one square meter of surface per second) and it is measured in moles or micromoles (µmol) of photons.
You can measure the number of photons hitting your plant (PPFD) using a quantum meter, predicting the potential photosynthetic capacity of your light.
You can measure the total number of photons emitted by a lamp (PPF)by putting it in an Ulbricht integrating sphere
So where we used to have luminous flux in lumens, we now have PPF in µmol/s, and where we used to have illuminance (light indicent on a surface) in lux, we now have PPFD in µmol/m2/s
Lamps with high lumens output are not necessary high par output lamps: some lamps with lower lumens output have higher micromole output.
Another important issue is of course the spectrum of a lamp. Micromoles alone is not enough - or blue and red LEDs would have worked
Doc
1. Philips Agro 400w 230v 660 uMol (output stabile, extra blue spectrum)
2. Philips Greenpower 400w 230v 725 uMol (output stabile)
600w
1. Philips SON-T plus 600w 230v 1045 uMol (output "instabile") output degrades fast
2. Philips SON-T Greenpower 600w 230v 1100 uMol (output stabile)
3. Philips SON-T Greenpower 600w 400v 1150 uMol (output stabile)
4. Philips SON-T Greenpower 600w 400v EL* 1170 uMol (output stabile) *specialy for high frequency electronic ballast >100.000 hertz
1000w
1. Philips SON-T Greenpower 1000w 400v EL* DE 1925 uMol (output stabile) in reality the lamp gives 2100 uMol at the start of its lifetime.
*specialy for high frequency electronic ballast <100.000 hertz
The standard measurements of light output have traditionally been done through the foot-candle, lumens and lux. They quantify how humans experience the intensity of light, based on the limited sensitivity of the human eye in the yellow/green area of the spectrum (around 550 nm). Plants however use a much wider spectrum for photosynthesis, called the PAR spectrum (Photo-synthetically Active Radiation), ranging from 400-700 nm
Human eye sensitivity versus plant sensitivity
Photosynthesis is not driven by brightness of the light according to the human eye or the energy of a photon (which varies for different colors) but purely by the number of photons in the PAR spectrum. You need about eight photons to bind one CO2 molecule. So to quantify potential photosynthesis it is all about the number of photons within the PAR spectrum hitting the plant. This is expressed as Photosynthetic Photon Flux (PPF – total photons emitted from a light source per second) and Photosynthetic Photon Flux Density (PPFD – the number of photons hitting one square meter of surface per second) and it is measured in moles or micromoles (µmol) of photons.
You can measure the number of photons hitting your plant (PPFD) using a quantum meter, predicting the potential photosynthetic capacity of your light.
You can measure the total number of photons emitted by a lamp (PPF)by putting it in an Ulbricht integrating sphere
So where we used to have luminous flux in lumens, we now have PPF in µmol/s, and where we used to have illuminance (light indicent on a surface) in lux, we now have PPFD in µmol/m2/s
Lamps with high lumens output are not necessary high par output lamps: some lamps with lower lumens output have higher micromole output.
Another important issue is of course the spectrum of a lamp. Micromoles alone is not enough - or blue and red LEDs would have worked
Doc
