Spectrum 318: BNA2 EditDelete
NARVA Lichtquellen GmbH + Co. KG http://www.narva-bel.de/
BIO vital 18W
|Ballast||- no ballast or default/unknown ballast -|
|Originator (measurement)||Frances Baines|
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|
|Colour Coordinate||( 0.31 ; 0.33 )||( 0.48 ; 0.42 )||( 0.29 ; 0.34 ; 0.3 )|
|CCT||6600 Kelvin||4100 Kelvin||4900 Kelvin|
|colour space||3-D-graph not implemented yet|
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.
The equilibrium of the photoproducts depends on the actual UV spectrum in the range 250 nm - 340 nm. With knowledge of the conversion probabilities and absorption spectra of 7DHC, PreD3, Tachysterol, and Lumisterol it is possible to calculate the ratio of photoproducts in equilibrium. This is based on scientific literature , however the constants that are used for the calculation are not well calibrated with experiments. It is therefore not a solid method, but I consider it useful as a first guess how natural a UV spectrum is.
Caveat: This evaluation is extremely sensitive to the qualitiy of the spectral measurement in the range 220 nm - 340 nm. High quality spectrometers and good background calibration is needed to get the noise below 300 nm low enough for this evaluation. Please check at least the UV graph above for noise.
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.
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
total ( 0 nm - 0 nm) 913 µW/cm² = 9.13 W/m² UVC ( 0 nm - 280 nm) 0.498 µW/cm² = 0.00498 W/m² UVB (EU) ( 280 nm - 315 nm) 3.63 µW/cm² = 0.0363 W/m² UVB (US) ( 280 nm - 320 nm) 4.59 µW/cm² = 0.0459 W/m² UVA+B ( 280 nm - 380 nm) 38.3 µW/cm² = 0.383 W/m² UVA1 ( 315 nm - 335 nm) 5.76 µW/cm² = 0.0576 W/m² UVA (EU) ( 315 nm - 400 nm) 42.5 µW/cm² = 0.425 W/m² UVA1(US) ( 320 nm - 350 nm) 11.6 µW/cm² = 0.116 W/m² UVA (US) ( 320 nm - 400 nm) 41.5 µW/cm² = 0.415 W/m² UVA2 ( 335 nm - 380 nm) 28.9 µW/cm² = 0.289 W/m² vis. UVA ( 350 nm - 380 nm) 22.1 µW/cm² = 0.221 W/m² VIS Rep3 ( 350 nm - 600 nm) 662 µW/cm² = 6.62 W/m² VIS Rep4 ( 350 nm - 700 nm) 870 µW/cm² = 8.7 W/m² purple ( 380 nm - 420 nm) 31.9 µW/cm² = 0.319 W/m² VIS ( 380 nm - 780 nm) 869 µW/cm² = 8.69 W/m² PAR ( 400 nm - 700 nm) 840 µW/cm² = 8.4 W/m² blue ( 420 nm - 490 nm) 265 µW/cm² = 2.65 W/m² green ( 490 nm - 575 nm) 282 µW/cm² = 2.82 W/m² yellow ( 575 nm - 585 nm) 24 µW/cm² = 0.24 W/m² orange ( 585 nm - 650 nm) 200 µW/cm² = 2 W/m² red ( 650 nm - 780 nm) 65 µW/cm² = 0.65 W/m² IRA ( 700 nm - 1400 nm) 26.7 µW/cm² = 0.267 W/m² IRB ( 1400 nm - 3000 nm) 0 µW/cm² = 0 W/m²
Erythema 0.453 UV-Index Pyrimidine dimerization of DNA 1.72 µW/cm² Photoceratitis 0.528 µW/cm² Photoconjunctivitis 0.473 µW/cm² DNA Damage 0.531 Vitamin D3 0.949 µW/cm² Photosynthesis 583 µW/cm² Luminosity 2510 lx Human L-Cone 372 µW/cm² Human M-Cone 319 µW/cm² Human S-Cone 203 µW/cm² CIE X 332 µW/cm² CIE Y 348 µW/cm² CIE Z 389 µW/cm² PAR 3860000 mol photons Extinction preD3 9.73 e-3*m²/mol Extinction Tachysterol 26.5 e-3*m²/mol Extinction Lumisterol 4.59 m²/mol Extinction 7DHC 5.25 m²/mol L-Cone 307 µW/cm² M-Cone 364 µW/cm² S-Cone 321 µW/cm² U-Cone 79.1 µW/cm² UVR - ICNIRP 2004 0.582 Rel Biol Eff Melatonin Supression 303 µW/cm² Blue Light Hazard 221 µW/cm² (87.9 µW/cm² per 1000 lx) CIE 174:2006 PreVit D3 1 µW/cm² Lumen Reptil 2540 "pseudo-lx" Vitamin D3 Degradation 0.984 µW/cm² Actinic UV 0.579 µW/cm²
Solarmeter 6.2 (UVB, pre 2010) 5.91 µW/cm² Solarmeter 6.5 (UV-Index, pre 2010) 0.282 Leybold UVB 3.95 µW/cm² Leybold UVA 24.9 µW/cm² Leybold UVC 0.435 µW/cm² DeltaOhm UVB 8.81 µW/cm² DeltaOhm UVC 1.48 µW/cm² Vernier UVB 1.45 µW/cm² Vernier UVA 18.4 µW/cm² Gröbel UVA 29.3 µW/cm² Gröbel UVB 2.22 µW/cm² Gröbel UVC 0.426 µW/cm² Solarmeter 6.4 (D3) 0.881 IU/min UVX-31 10.5 µW/cm² IL UVB 0.00248 µW/cm² IL UVA 30 µW/cm² Solarmeter 6.5 (UVI, post 2010) 0.245 UV-Index Solarmeter 6.2 (UVB, post 2010) 3.53 µW/cm² (Solarmeter Ratio = 14.4) Solarmeter AlGaN 6.5 UVI sensor 2.7 UV Index GenUV 7.1 UV-Index 0.166 UV-Index Solarmeter 10.0 (Global Power) 9.17 W/m² Solarmeter 4.0 (UVA) 0.456 mW/cm²