Spectra of different light sources measured with hi resolution UV-VIS spectro meter :
Comparisson of a DL50 with a overpowered D2S from GE: The GE bulb has less blue spectral intensive lines than the DL50. The typical xenon look of the GE is lost and there's less light output as well. As a conclusion a 50W Xenon system requires a 50W bulb.
DUV35W Philips bulb
This pictures shows spectral data measured with DUV bulb from Brightstar at different wattages. The spectral distribution at a lower bulb wattage especially at 25W seems to be more efficient in respect of ultraviolett light per watt .
Spectral distribution of a 21 W HID bulb from Brightstar without UV filter tube. This HID has a very short electrode distance of approximately 3,5 mm. The spectrum shows extremely sharp emission lines. To the infrared region there is arelatively low intensity, which indicates a better lumen/wattage performance compared to DC arc tubes.
The spectral distribution of the 32 W HID bulb from Brightstar without UV filter tube performs great even intended as a UV light source. The slightly bigger arc compartment has a positive influence on the spectral color performance as well as on the better light distribution for optical reflector designs.
Spectral distribution of a 35 W HID D4S Xeneco bulb from Philips. This new HID bulb is free of mercury and has much lower bulb voltage as the mercury types. Because there is no mercury anymore the strong lines in the blue at 404 und 463 nm are missing.
Spectral distribution of a 35W Brightstar reflector bulb at 35W and 21W. This reflector bulb has a front cover glas. The glasreflector has a partial transmission backwards, which reduces the infrared light at full power.
Cold LED White light
There is one main emission line from the electrons, when they losse the amount of energy of the forward voltage drop of the junction. This line is getting broader and less high with higher temperature. The light of the dye does not change very much. There is no UV light - however there is no real balance, because of relative low green and red. Because water filters light not equally LED light gives poor color rendering under water and other situations.
The light of a neon tube has again sharp lines, but it has good balanced color output..
The sun has a contenious emitting spectrum with absorption lines. High energy radiation is blocked by the atmosphäre. However because of the missing ozone nowadays there is more dangerous UV light. Gas atoms and molecules of natural atmospehre but also air polution are filtering lines out of the originale spectrum. Therefore the sunlight depends strongly on the season, weather, position and other environmental inflluences.