Skylight just at noon on a horizontal plane in Lund
LARS OLOF BJÖRN. 2007. The Science of Life and Light. 2nd ed. New York: Springer 978-0-387-72654-0.
Spectrum 32: SUN Edit
DeleteMeasurement
| Brand |
other other |
|---|---|
| Lamp Product |
Sun Direct sunlight |
| Lamp ID |
SUN (01/2000) |
| Spectrometer | - |
| Ballast | - no ballast or default/unknown ballast - |
| Reflector | |
| Distance | 0 cm |
| Age | 0 hours |
| Originator (measurement) | Publication |
Database entry created:
Sarina Wunderlich
28/Jan/2010 ; updated:
Sarina Wunderlich
9/Oct/2011
Colorimetry
Colorimetry is the science to describe physically the human color perception. The wavelength range 380 nm - 780 nm is visible to humans and detected by three different photoreceptors. Many Reptiles see the range 350 nm - 800 nm and have an additional UV photoreceptor in their retina.
Whereas a spectrometer measures the intensity in every tiny wavelength interval resulting in thousands of individual intensities, the human eye only measures three intensities detected by the three cones. The same is true for the reptile eye with usually three or four photoreceptors. Effectively the detailled spectrum displayed above reduces to a much compacter bar graph displayed below. The photoreceptor sensitivites from these L-Cone, M-Cone, S-Cone, and U-Cone are used, they are chosen as an average of measured reptile photoreceptor sensitivity curves. The bar graph also shows as reference the intensity seen by the three or four photoreceptors for average sunlight (id 1).
From these three numbers the colour coordinate and the correlated colour temperature for humans are calculated using the CIE standard method. I adapted this concept to a "3 cone reptile (M,S,U)" and a "4 cone reptile (L,M,S,U)". I am sure, that this adaption to other colour spaces makes sense mathematically and this is also done in scientific research regarding colour vision of animals, however I have not seen calculation of colour temperatures for other animals in the scientific literature. Even if it is hypothetical, at least this shows, how arbitrary the colour temperature is, and that the colour temperature calculated for humans does not apply to reptiles. The colour spaces also show the colour coordinates of different phases of daylight ((ids 1, 338 – 451, 511 – 513 ), indicated by crosses, coloured in the appriximate colour perceived by a human.
| Human (CIE) | 3 cone reptile | 4 cone reptile | |
|---|---|---|---|
| Cone Excitation | |||
| Colour Coordinate | ( 0.24 ; 0.24 ) | ( 0.27 ; 0.38 ) | ( 0.13 ; 0.23 ; 0.33 ) |
| CCT | 46000 Kelvin | 9100 Kelvin | 12000 Kelvin |
| distance | 0.046 | 0.057 | |
| colour space | 3-D-graph not implemented yet |
Vitamin D3 Analysis
Vitamin D3 is produced by UVB radiation around 300 nm. 7DHC/ProD3 present in the skin is converted to PreD3 when absorbing an UV photon. PreD3 can be converted back to ProD3, to Lumisterol, or to Tachysterol when absorbing another UV photon or can be converted to Vitamin D3 in a warm environment.
This process prevents any overdose of vitamin D3 from UV radiation with a spectrum similar to sunlight. As a comparison the solar spectra at 20°(id:14) and at 85°(id:21) solar angle are shown.
The ratio of the two solarmeters 6.2 (UVB) and 6.5 (UV index) readings has proven a useful and very simply number to acess the spectral shape in the vitamin-d3-active region.
Effective Irradiances
Effective irradiances are calculated for all ranges, actionspectra and radiometers currently present in this database.
The calculation method is a numerical implementation (Simpson's rule) of the formula
To learn more about calculating effective irradiances and radiometers I recommend this excellent report on UVB meters: Characterizing the Performance of Integral Measuring UV-Meters (pdf).
The numbers in the following tables can also be used to estimate certain (effective) irradiances from radiomer readings. Example: If the database lists
- range: UVB (US) = 13.8 µW/cm²
- radiometer: Solarmeter 6.2 = 19.6 µW/cm²
Ranges
total ( 0 nm - 0 nm) 5650 µW/cm² = 56.5 W/m² UVC ( 0 nm - 280 nm) 0 µW/cm² = 0 W/m² non-terrestrial ( 0 nm - 290 nm) 0 µW/cm² = 0 W/m² total2 ( 250 nm - 880 nm) 5650 µW/cm² = 56.5 W/m² UVB (EU) ( 280 nm - 315 nm) 61.8 µW/cm² = 0.618 W/m² UVB (US) ( 280 nm - 320 nm) 117 µW/cm² = 1.17 W/m² UVA+B ( 280 nm - 380 nm) 1280 µW/cm² = 12.8 W/m² Solar UVB ( 290 nm - 315 nm) 61.8 µW/cm² = 0.618 W/m² UVA D3 regulating ( 315 nm - 335 nm) 325 µW/cm² = 3.25 W/m² UVA (EU) ( 315 nm - 380 nm) 1220 µW/cm² = 12.2 W/m² UVA2 (medical definition) ( 320 nm - 340 nm) 372 µW/cm² = 3.72 W/m² UVA (US) ( 320 nm - 380 nm) 1170 µW/cm² = 11.7 W/m² UVA1 (variant) ( 335 nm - 380 nm) 896 µW/cm² = 8.96 W/m² UVA1 (medical) ( 340 nm - 400 nm) 1180 µW/cm² = 11.8 W/m² vis. UVA ( 350 nm - 380 nm) 599 µW/cm² = 5.99 W/m² VIS Rep3 ( 350 nm - 600 nm) 4200 µW/cm² = 42 W/m² VIS Rep4 ( 350 nm - 700 nm) 4790 µW/cm² = 47.9 W/m² purple ( 380 nm - 420 nm) 873 µW/cm² = 8.73 W/m² VIS ( 380 nm - 780 nm) 4370 µW/cm² = 43.7 W/m² PAR ( 400 nm - 700 nm) 3800 µW/cm² = 38 W/m² blue ( 420 nm - 490 nm) 1500 µW/cm² = 15 W/m² green ( 490 nm - 575 nm) 1040 µW/cm² = 10.4 W/m² yellow ( 575 nm - 585 nm) 80.8 µW/cm² = 0.808 W/m² orange ( 585 nm - 650 nm) 450 µW/cm² = 4.5 W/m² red ( 650 nm - 780 nm) 430 µW/cm² = 4.3 W/m² IRA ( 700 nm - 1400 nm) 173 µW/cm² = 1.73 W/m² IRB ( 1400 nm - 3000 nm) 0 µW/cm² = 0 W/m²
Actionspectra
Erythema 3.25 UV-Index Pyrimidine dimerization of DNA 45.1 µW/cm² Photoceratitis 4.67 µW/cm² Photoconjunctivitis 0.0484 µW/cm² DNA Damage 0.156 Vitamin D3 14.6 µW/cm² Photosynthesis 2850 µW/cm² Luminosity 8050 lx Human L-Cone 1150 µW/cm² Human M-Cone 1100 µW/cm² Human S-Cone 1270 µW/cm² CIE X 1100 µW/cm² CIE Y 1100 µW/cm² CIE Z 2290 µW/cm² PAR 17300000 mol photons Extinction preD3 124 e-3*m²/mol Extinction Tachysterol 454 e-3*m²/mol Exctincition PreD3 63600 m²/mol Extinction Lumisterol 8.81 m²/mol Exctincition Tachysterol 739000 m²/mol Extinction 7DHC 3.88 m²/mol L-Cone 898 µW/cm² M-Cone 1590 µW/cm² S-Cone 2250 µW/cm² U-Cone 2060 µW/cm² UVR - ICNIRP 2004 1.94 Rel Biol Eff Melatonin Supression 1790 µW/cm² Blue Light Hazard 1500 µW/cm² (186 µW/cm² per 1000 lx) CIE 174:2006 PreVit D3 16.2 µW/cm² Lumen Reptil 13900 "pseudo-lx" Vitamin D3 Degradation 24.2 µW/cm² Actinic UV 1.94 µW/cm² (2.41 mW/klm) Exctincition Lumisterol 16100 m²/mol Exctincition 7DHC 6130 m²/mol Exctincition Toxisterols 14200 m²/mol
Broadbandmeters
Solarmeter 6.2 (UVB, pre 2010) 163 µW/cm² Solarmeter 6.5 (UV-Index, pre 2010) 4.43 Leybold UVB 110 µW/cm² Leybold UVA 864 µW/cm² Leybold UVC 0 µW/cm² DeltaOhm UVB 364 µW/cm² DeltaOhm UVC 36.2 µW/cm² Vernier UVB 35 µW/cm² Vernier UVA 825 µW/cm² Gröbel UVA 1000 µW/cm² Gröbel UVB 50.1 µW/cm² Gröbel UVC -0.024 µW/cm² Solarmeter 6.4 (D3) 13.8 IU/min UVX-31 414 µW/cm² IL UVB 0.0753 µW/cm² IL UVA 996 µW/cm² Solarmeter 6.5 (UVI, post 2010) 3.9 UV-Index Solarmeter 6.2 (UVB, post 2010) 119 µW/cm² (Solarmeter Ratio = 30.4) Solarmeter AlGaN 6.5 UVI sensor 57.3 UV Index GenUV 7.1 UV-Index 3.56 UV-Index Solarmeter 10.0 (Global Power) 45.2 W/m² Solarmeter 4.0 (UVA) 15.3 mW/cm² LS122 0 W/m² ISM400 25.2 W/m²