Sledge,

I found something wrong with this website. In fact, its in one of the first sentences in the paragraph about blue bulbs.

"White light is made up of every color of light mixed together."

WRONG. White the color, is the absence of pigment. Webster says "white" is "free from color". BLACK is every color mixed together. We did an expirement in oh, 3rd grade or so that proved that. If you put some dye on a strip of black paint, you get all sorts of colors on that strip.

I made a mistake in saying that color and brightness go hand in hand. What I meant to say was that color temp in Kelvin and the amount of "blueness" go hand in hand. As the color temp goes up, light (NOT BULBS, strictly light) appears more and more blue. A blue tinted bulb however, screens out everything BUT blue, which wouldn't make it any brighter than a non tinted one. Lumens is the correct way to measure brightness correct ????

 

We also did an experiment in 3rd grade where we used a prism to take white light and separate it into the seven colors of the rainbow. The website is correct.

http://en.wikipedia.org/wiki/Prism_%28optics%29

 

Actually both of your statements about color are right, but they're not interchangeable. White light IS the combination of all colors of light. And as far as pigment goes, black (actually the truly correct color is brown) is the combination of all pigments, generally speaking. These statements are both correct, one refers to additive color and the other to subtractive.

The color "temperature" refers to the combination of wavelengths of light produced. White light is the combination of all wavelengths (and full spectrum light includes all the non visible light too, including what we normally think of as radio waves, all are light) but not all lamps produce the same spectral components at the same intensity. The higher the frequency the "bluer" the light appears because it contains more of the higher frequencies of visible light (closer to the blue end of the rainbow). Using a blue colored bulb actually does just filter out some of the other frequencies, in essence reducing the total light emitted, actually making it less intense in total light output, even if it seems brighter because of the color. Lamps that produce bluer light may actually output higher intensity in that spectral band than other bulbs and thus produce more light of that color for the same energy consumption, so measuring them as "brighter" can sometimes be deceptive. there's no more total energy emitted compared to an equivalent wattage bulb, but they may produce more energy at a particular frequency range than the others because they're not "wasting" as much energy producing lower frequencies.

 

So before the mud starts getting thrown around...

Some basic physical misconceptions running around here:

- Pigments and spectral colors are different. Mix paint pigments, you get black or brown muck. Mix equal powers of spectral colors and you get white.

- The WAVELENGTH (spectral color) that appears brightest to the human eye is GREEN. Right in the middle of the visible spectrum. Go figure. Green laser pointers look much brighter yet actually put out less optical power than red.

- The sky is blue not because of absorption. Blue is not abosrbed by the atmosphere appreciably more than red. Blue is Rayleigh scattered in all directions by molecules more efficently (a function of wavelength^-4), causing it to separate out from the rest and scattering all around, making the sky blue. Larger particles cause Mie scattering, which is directional and not strongly wavelength dependent- causing the sky to look whiter closer to the sun when the sun is high. At sunset, the sun's light travels through much more of the atmosphere to reach you, causing much more Rayleigh scattering of the blue, and also significant green scattering- leaving red. This is enhanced when there is a lot of dust or aerosols in the atmosphere, like after several days of high pressure and low wind, or during large fires.

- In rain, blue scatters as before and is compounded by the fact that it refracts inside raindrops more severely than red so it is bent out of the path you want to illuminate. Raindrops themselves actually cause very little scattering.

- In fog, the droplets are much smaller but still larger than the wavelength of light, and Mie scattering dominates. So white light still looks white, red looks red red and blue still looks blue when it gets to its target. But there's less of it because of the scattering. Lots less- that lost light has been bounced in the other directions- which is why you can see the beam in fog. And some of that has been scattered right back into your eyes, degrading your vision. That's why low beams are used, and fog lights are aimed low- to reflect off the ground and less into your eye.

- Yellow foglamps: Mie scattering, as I said, is not very dependent on color for the size droplets present in fog. Any color will penetrate with the same efficiency, so it comes down to finding the easiest, "brightest" color to generate. A single color is preferred to reduce image blurring caused by the high color dispersion through water. Yellow is used mostly for historical reasons because its close to the color of lamps anyway and could be filtered without too much loss of brightness (think about when they first came out, only incandescent lamps were available). Its also perceived brightly by the human eye, very close to green. Red/green couldn't be used (stoplights, emergency vehicles), and blue still has the Rayleigh issue. So yellow it was, and continues today.

- The 'colors' of HID lights are in fact from the projector system in the lens causing dispersion- the color you see changes with viewing angle. They are arclamps, which do 'burn' hotter than tungsten filaments, so there is more blue spectral content to begin with as well.

 

Woops, sorry Sledge. I assumed that pigment would be the same as light, but seeing as how we did the expirement too, and I just plain out forget that we did it, I should have known that. I mean, after the whole battle if light is a wave or a particle, you shouldn't assume that "apples will always be apples" when it comes to light, or color for that matter. I guess what my friend says is true. "Assumption is the mother of all f-ups"

gonavy: You're right about green being the brightest color now that I think about it. For some reason that doesn't make sense to me either, my 8th grade science prof said that. Thats why fire engines are sometimes a funky shade of green. Traditionally they were red, but I've seen some here in Los Angeles (from certain cities) that they're a shade of green (a sorta pale one). Problem is since we're ALL accustomed to seeing them as red its hard to immediately think, "big, green, oh, its a fire truck", so they're hesitant to paint more of them a greenish color is my guess.

So anyway, I've come to realize now because I've actually thought about what I know about light and read about it, that I want my light to be a little BLUER than what the HCH has now. I don't want it to be a TINTED glass blue, I want it to be BLUE because its of a higher temp than the halogens they have now. Slyvania has cool blues but I think I want them to be bluer than that, slightly more.

Will Silverstars be better ???? Are they more "blue" ???? I just read that for the North American arm of Osram (Sylvania) they have a higher color temp, so they should be. They are MORE bright than cool blues, and they have a shorter life. So now I'm confused. Here is what I want:

I want the light to be bluer than now. They don't have to be SUPER blue like the tinted fake ones are, just a touch of blue when you look at them. I want them to be BRIGHTER than they are now. I don't care about changing them more often. Once, even twice a year is fine with me. They're not that expensive. So what brand/combination light does ANYONE recommend ???? I would also probably purchase the OSRAM European version of bulbs since they seem to be brighter and last longer, but I shall research this now after I post this to double check.

AND MOST IMPORTANTLY, WHAT NUMBER BULB DOES THE HCH II USE ???? 9007, 9004, what ????!!!! I want to tear my hair out since I can't find the info....