Overgrow Independently Measured Lamp Spectra
Methods and descriptions
Measurement device:
Stellarnet CXR-SR-100 w/ CR2 Cosine Adapter.
The measurements in this thread are single point, 18 inches from the center of the light source. This is for consistency and is the most relevant metric for verifying/comparing against manufacturer specifications. It is a direct measurement. This thread is namely to capture the spectrum distribution for various lamps which will be consistent over the illuminated area. The total power will vary depending on the distance to the source, the spread of the lamp / optics, the size/nature/reflectivity of the room, and the cosine angle to lamp while the spectrum will remain consistent.
With that noted, an important metric when designing your room for lighting is PPFD. This is the intensity measured and averaged at various intervals over a defined area. The spread of the light output over an area defines the useful working photons. Where inclined, PPFD and/or PAR maps are measured using an Apogee PAR sensor noting the caveat that the room itself will have an impact on the actual PAR maps due to reflection (e.g. measurements are partially indirect).
As an example, in some cases the measured power (W) appears much greater than expected. This is because the measurements using the spectrometer is based on the illumination of a square meter. These measurements are spot measurements at the center of the lamp. We calculate the power assuming the square meter is evenly illuminated. In reality, the square meter is not evenly illuminated, the power would decrease as we move away from the center, and the total power across that square meter would significantly less. A focused spot like lamp would indicate greater power output as compared to a diffuse / spread-out lamp even if the two lamps produced the same PPF. So, keep this in mind when reading through this information. PPFD, the type of room, etc is equally important.
Definitions:
PAR - range of photosynthetically active radiation. Unless noted otherwise, typically 400-700nm. This is the most common range utilized when describing horticultural lighting although there are wavelengths outside of this range that are also sometimes considered. If so, the wavelength should be defined. It is common to see PAR used interchangeable with PPF as a metric of power over 400-700nm.
PPF - Integral power across the PAR range of wavelengths.
SPD - Spectral power distribution. Absolute photon flux as measured across the spectra. A spectrometer will measure photon flux in discrete “bins” of frequencies. From these “bins”, one can calculate the total power across the spectrum or power within a narrow band of frequencies. (e.g. power in the blue spectrum). The spectral graphs generated from a calibrated spectrometer details SPD. An uncalibrated spectrometer generates spectrum distribution but would not contain accurate power information (just relative power).
YPF - yield photon flux. Weighted photosynthetic yield measurement across 360 to 760nm.
YPF/PPF - the ratio between the PAR and YPF calculations. This metric exposes how closely the overall light output in the PAR region targets the traditional quantum efficiency curves. The closer this is to one, the closer of a match. This metric is bit of an oddball. Matching an efficiency curve with the intensity output makes some sense in that your targeting more efficient conversion but such matching doesn’t necessarily address what ratios the plant actually needs under various circumstances. However, it appears that this metric is utilized by some OEMs to design their spectra and they have been relatively successful. Adding more green, for instance, will show a decrease in this ratio.
PPE or PSS - estimated phytochrome photoequilibrium. Also termed PSS. Ratio of Pfr to Pr. Pfr : ( Pfr + Pr ) where Pr is the photon flux integral across 600-700 nm waveband. Pfr is the integral across the 700-800 nm waveband. This acronym is also used when describing lamp efficiency. Try not confuse that in this context.
PPE - Photosynthetic photon efficacy. This is another definition of PPE. It is a relative ratio of the input power that is converted to usable photons. The higher the number, the higher the efficiency of the lamp.
DLI index : the integrated amount of PAR light your crop would see over the period of a 12 hour day under the test conditions.
Notes:
PAR (PFD) can be misleading if you are not paying attention. The standard for PAR is between 400 and 700nm. For non-traditonal “McCree” spectra, the PAR measurement may not capture the majority of the power. For example, UV and far-red will fall outside of the PAR spectrum though there are good reasons to consider implementing a lighting strategy that includes these spectra. YPF has a broader range but is weighted (by committee) depending on the photosynthetic action spectra. While this might be valid, it can be confusing if you are looking for raw irradiance values that are not weighted. The integral radiance numbers are the raw radiant power measured and can be converted to umols by using an estimated conversion factor such as 4.2 or by converting each wavelength bin to equivalent photons (mols) and then integrating over your desired range.
P.S. the coloring of the following graphs is artificial. The actual colors may not perfectly line up with what would be perceived but is instead simply meant as a guide to the general color red/blue/green/etc.
P.P.S sometimes I forget to relabel the graph titles, so please ignore it if it doesn’t match what you’d expect.
Heliospectra
Heliospectra 601G
(All spectrum set at 100%, open air, single point, 18" distance from center of lamp):
Integral radiant (400-700nm): 197.9 W/m^2
Integral radiant (350-840nm): 201.9 W/m^2
PAR (400-700nm): 993.6 umol / m^2 s
YPF (360-760nm) : 887.6 umol / m^2 s
YPF/PFD: 0.89
PSS: 0.87
DLI index [12 hours] : 42.9400-500nm Blue : 15.50%
500-600nm Green : 11.57%
600-700nm Red : 72.93%287-320nm UVB : 0.01%
320-399nm UVA : 0.10%
400-475nm Violet-Blue : 14.08%
476-550nm Cyan-Green : 6.12%
551-700nm Green-Yellow-Red : 77.47%
701-850nm Far Red-NearIR : 2.23%Power consumption: 512.82W
Heliospectra 601C
(All spectrum set at 100%, open air, single point, 18" distance from center of lamp):
Integral radiant (400-700nm): 154.9 W/m^2
Integral radiant (350-840nm): 177.6 W/m^2
PAR (400-700nm): 759.7 umol / m^2 s
YPF (360-760nm) : 693.5 umol / m^2 s
YPF/PFD: 0.91
PSS: 0.82
DLI index [12 hours] : 32.8400-500nm Blue : 19.90%
500-600nm Green : 13.52%
600-700nm Red : 66.58%287-320nm UVB : 0.01%
320-399nm UVA : 0.12%
400-475nm Violet-Blue : 15.61%
476-550nm Cyan-Green : 6.27%
551-700nm Green-Yellow-Red : 62.74%
701-850nm Far Red-NearIR : 15.25%Power consumption: 473.28W
Fluence Bioengineering
Fluence RAY44 PfrSpec
(open air, single point, 18" distance from center of lamp)
Integral radiant (400-700nm): 1.2 W/m^2
Integral radiant (700-800nm): 22.3 W/m^2
PAR (400-700nm): 7.06 umol / m^2 s
YPF (360-760nm) : 24.32 umol / m^2 s
YPF/PFD: 3.44
PSS: 0.14
DLI index [12 hours] : 0.3400-500nm Blue : 0.45%
500-600nm Green : 0.64%
600-700nm Red : 98.91%287-320nm UVB : 0.01%
320-399nm UVA : 0.01%
400-475nm Violet-Blue : 0.02%
476-550nm Cyan-Green : 0.02%
551-700nm Green-Yellow-Red : 5.52%
701-850nm Far Red-NearIR : 94.42%
Fluence RAY44 UVSpec
(open air, single point, 18" distance from center of lamp)
Integral radiant (400-700nm): 28.5 W/m^2
Integral radiant (350-840nm): 34.1 W/m^2
PAR (400-700nm): 97.53 umol / m^2 s
YPF (360-760nm) : 81.82 umol / m^2 s
YPF/PFD: 0.84
PSS: 0.55
DLI index [12 hours] : 4.2400-500nm Blue : 99.99%
500-600nm Green : 0.01%
600-700nm Red : 0.00%287-320nm UVB : 0.02%
320-399nm UVA : 19.07%
400-475nm Violet-Blue : 80.89%
476-550nm Cyan-Green : 0.01%
551-700nm Green-Yellow-Red : 0.00%
701-850nm Far Red-NearIR : 0.00%
Vyprx Plus Greenhouse Spectrum
(open air, single point, 18" distance from center of lamp)
Integral radiant (400-700nm): 215.5 W/m^2
Integral radiant (350-840nm): 221.9 W/m^2
PAR (400-700nm): 997.1 umol / m^2 s
YPF (360-760nm) : 867.6 umol / m^2 s
YPF/PFD: 0.87
PSS: 0.85
DLI index [12 hours] : 43.1400-500nm Blue : 23.71%
500-600nm Green : 40.52%
600-700nm Red : 35.76%287-320nm UVB : 0.01%
320-399nm UVA : 0.16%
400-475nm Violet-Blue : 17.77%
476-550nm Cyan-Green : 21.82%
551-700nm Green-Yellow-Red : 56.66
701-850nm Far Red-NearIR : 3.58%
Spydr 2P PhysioSpec Indoor
(open air, single point, 18" distance from center of lamp)
Integral radiant (400-700nm): 186.4 W/m^2
Integral radiant (350-840nm): 192.3 W/m^2
Lumens (m^2) : 54821
Spectrometer PFD (400-700nm): 889.56 umol / m^2 / s
Spectrometer PFD (350-840nm): 925.5 umol / m^2 / s
Quantum Sensor PFD (400-700nm): 850.4 umol / m^2 / s
YPF (360-760nm) : 791.86 umol / m^2 / s
YPF/PFD: 0.89
PSS: 0.86
DLI index [12 hours] : 38.4Blue(400 - 500nm): 16.24%
Green(500 - 600nm): 38.14%
Red(600 - 700nm): 45.62%UVB(287-320nm): 0.01%
UVA(320-400nm): 0.12%
Violet_Blue(400-475nm): 11.91%
Cyan_Green(475-550nm): 18.58%
Green_Yellow_Red(550-700nm): 65.56%
FarRed_NearIR(700-850nm): 3.82%
Mars Hydro
MH-SP-250
(open air, single point, 18" distance from center of lamp)
Integral radiant (400-700nm): 100.6 W/m^2
Integral radiant (350-840nm): 104.5 W/m^2
Lumens (m^2) : 32794.83
Spectrometer PAR (400-700nm): 475.58 umol / m^2 s
Quantum Sensor PAR : 451.6 umol / m^2 s
YPF (360-760nm) : 424.57 umol / m^2 s
YPF/PFD: 0.89
PSS: 0.85
DLI index [12 hours] : 20.5400-500nm Blue : 15.98%
500-600nm Green : 43.90%
600-700nm Red : 40.11%287-320nm UVB : 0.01%
320-399nm UVA : 0.17%
400-475nm Violet-Blue : 13.42%
476-550nm Cyan-Green : 17.65%
551-700nm Green-Yellow-Red : 64.04%
701-850nm Far Red-NearIR : 4.71%
Vivosun
VS4300
(open air, single point, 18" distance from center of lamp)
Integral radiant (400-700nm): 179.9 W/m^2
Integral radiant (350-840nm): 183.0 W/m^2
Lumens (m^2) : 54821
Spectrometer PFD (400-700nm): 837.75 umol / m^2 / s
Spectrometer PFD (350-840nm): 856.39 umol / m^2 / s
Quantum Sensor PFD (400-700nm): 844.7 umol / m^2 / s
YPF (360-760nm) : 728.5 umol / m^2 / s
YPF/PFD: 0.87
PSS: 0.85
DLI index [12 hours] PAR : 36.2 400-500nm Blue : 21.31%
500-600nm Green : 42.32%
600-700nm Red : 36.37%287-320nm UVB : 0.01%
320-399nm UVA : 0.13%
400-475nm Violet-Blue : 15.21%
476-550nm Cyan-Green : 22.69%
551-700nm Green-Yellow-Red : 59.78%
701-850nm Far Red-NearIR : 2.19%
Unbranded
E27 10W Ultra Bright UV Ultraviolet Color Purple Light 160LED Lamp Bulb 110v
(open air, single point, 18" distance from center of lamp)
Integral radiant (400-700nm): 6.85 W/m^2
Integral radiant (350-1100nm): 10.70 W/m^2
PAR (400-700nm):
YPF (360-760nm) :
YPF/PFD:
PSS:
DLI index [12 hours] : 400-500nm Blue : 97.73%
500-600nm Green : 1.07%
600-700nm Red : 1.20%287-320nm UVB : 0.03%
320-399nm UVA : 34.28%
400-475nm Violet-Blue : 60.47%
476-550nm Cyan-Green : 0.63%
551-700nm Green-Yellow-Red : 1.10%
701-850nm Far Red-NearIR : 3.49%
5W E27 UV Ultraviolet Purple LED Spotlight Bulb Home Lamp Light AC 85-265V
(open air, single point, 18" distance from center of lamp)
Integral radiant (400-700nm): 18.29 W/m^2
Integral radiant (350-1100nm): 25.99 W/m^2
PAR (400-700nm):
YPF (360-760nm) :
YPF/PFD:
PSS:
DLI index [12 hours] : 400-500nm Blue : 99.50%
500-600nm Green : 0.38%
600-700nm Red : 0.12%287-320nm UVB : 0.01%
320-399nm UVA : 31.99%
400-475nm Violet-Blue : 67.44%
476-550nm Cyan-Green : 0.23%
551-700nm Green-Yellow-Red : 0.21%
701-850nm Far Red-NearIR : 0.12%
Note: As discussed earlier, while the measured power (W) appears much greater than the specified power, notice that the measurement is based on the illumination of a square meter. The measurements for spectrum are spot measurements at the center of the lamp and we calculate the power assuming the square meter is evenly illuminated. In reality, the square meter is not evenly illuminated and the total power across that area would be much less. A focused spot like lamp will indicate greater power output as compared to a diffuse / spread-out lamp.
Comparative Spectras
Inside of a greenhouse natural light filtered by glass glazing + supplemental:
Integral radiant (400-700nm): 252 W/m^2
Integral radiant (350-840nm): 297 W/m^2
PAR (400-700nm): 1042 / m^2 s
YPF (360-760nm) : 919 / m^2 s
PSS: 0.76
DLI index [12 hours] : 400-500nm Blue : %
500-600nm Green : %
600-700nm Red : %287-320nm UVB : %
320-399nm UVA : %
400-475nm Violet-Blue : %
476-550nm Cyan-Green : %
551-700nm Green-Yellow-Red : %
701-850nm Far Red-NearIR : %
Sunlight, 11AM EST Northeast US. Current conditions partially cloudy.
Integral radiant (400-700nm): 341.7 W/m^2
Integral radiant (350-840nm): 483.8 W/m^2
PAR (400-700nm): 1580 umol / m^2 s
YPF (360-760nm) : 1412 umol / m^2 s
YPF/PFD: 0.89
PSS: 0.72
DLI index [12 hours] : 68.3400-500nm Blue : 25.49%
500-600nm Green : 35.45%
600-700nm Red : 39.05%287-320nm UVB : 0.06%
320-399nm UVA : 3.06%
400-475nm Violet-Blue : 11.54%
476-550nm Cyan-Green : 16.07%
551-700nm Green-Yellow-Red : 37.17%
701-850nm Far Red-NearIR : 32.09%Power consumption: Free!
Sunlight Tree Shaded, 11AM EST Northeast US. Current conditions partially cloudy.
Integral radiant (400-700nm): 39.7 W/m^2
Integral radiant (350-840nm): 60 W/m^2
PAR (400-700nm): 173.9 umol / m^2 s
YPF (360-760nm) : 154.2 umol / m^2 s
YPF/PFD: 0.89
PSS: 0.67
DLI index [12 hours] : 7.5400-500nm Blue : 38.67%
500-600nm Green : 35.22%
600-700nm Red : 26.12%287-320nm UVB : 0.20%
320-399nm UVA : 7.39%
400-475nm Violet-Blue : 17.19%
476-550nm Cyan-Green : 16.93%
551-700nm Green-Yellow-Red : 25.35%
701-850nm Far Red-NearIR : 32.95%Power consumption: Free!
So, good catch.
. Which ever you prefer.
