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New Car Headlamps

Published : 28th March 2005

Anybody know if these bluish headlamps on the newer cars are close to daylight temp? How do they photograph? Are they halogen or of HMI lineage?

Tom McDonnell
DP/Operator
New Orleans, La


class="style9">>Anybody know if these bluish headlamps on the newer cars are close to >daylight temp? How do they photograph? Are they halogen or of HMI >lineage?

Most likely xenon :

http://www.howstuffworks.com/question387.htm

Art Adams, DP [film|hdtv|sdtv]
Mountain View, California - "Silicon Valley"
http://www.artadams.net/


They are xenon and probably bluer than daylight, although I've never measured them (nor photographed them.)

Wade K. Ramsey, DP
Dept. of Cinema & Video Production
Bob Jones University
Greenville, SC 29614


Although definitely bluish (arc light source), I also often see a color shift when viewed from various angles, so I suspect there may be some dichroic heat/UV filtration on the reflectors being used :

http://www.sylvania.com/xenarc/prodinfo.htm

John Pytlak
EI Customer Technical Services
Research Labs, Building 69
Eastman Kodak Company
Rochester, New York 14650-1922 USA
http://www.kodak.com/go/motion


They're HMI, and come in a few different color temperatures.

For a quick tutorial, go to eBay and search for HMI or HMI headlight and you'll learn a lot. These lamps are very cheap -- anyone making their own 12v HMI soft lights out of them? Seems like a simple DIY project...

Then again, so does making your own HD camera to some crackpots out there.

Jeff "or your own telecine" Kreines


Jeff "or your own telecine" Kreines wrote:

>>They're HMI, and come in a few different color temperatures.

>>For a quick tutorial, go to eBay and search for HMI or HMI headlight and >you'll learn a lot.

??? Ebay search turned up nothing on "HMI headlights", and a few lamps and mp fixtures on "HMI". Where are these 12v HMI headlight lamps? All the ones I know of are xenon, see the Sylvania ref. Pytlak gave.

And they cost an arm and a leg, around $1K per lamp, last I heard.

Wade K. Ramsey, DP
Dept. of Cinema & Video Production
Bob Jones University
Greenville, SC 29614


Wade Ramsey wrote:

>>And they cost an arm and a leg, around $1K per lamp, last I heard.

Sorry. Search headlight xenon...they're Xenon. Wasn't thinking.

Jeff "plonk!" Kreines


I too, have always noticed these in oncoming traffic and have wondered

I'd be quite curious what color these end up reading. I don't have a color meter. Anybody wanna take a gander?

Roderick (Az. D.P.)
www.restevens.com
12on12off


 

Did a job last year with adapted HID bicycle lights as on camera lights.

Pic here http://tinyurl.com/3b8rj

We called the manufacturer and elementally received specs from the bulb manufacture. They were roughly 6000k temp and 90 CRI but, I've forgotten the except specs as I wasn't that impressed with the setup.

The bike light would run for four hours on its battery. They had a very narrow beam focus (spot), once diffused through a layer of 216 the output wasn't as impressive. With a wide angle bulb / reflector they would be wonderful.

Dave Winters
DP L.A.


Hi,

>> They're HMI, and come in a few different color temperatures.

Just as a technical side note, they're not actually Xenon, at least not xenon like a projector lamp. Most of them use the Philips D2 series lamps which are actually a metal halide type with a Xenon gas fill, which makes them much more like HMI in mode of operation.

Think of them like an HMI with Xenon rather than mercury vapour fill.

>>I'm sure some company will finally bring out a Xenon arc for movie use.

I believe PAG already have. Their tiny 10W light uses the same topology as the Xenon HID headlamps, the bulb in this case being intended for medical applications by Welch-Allyn. Possibly the smallest arc light ever made. Also packaged for bicycles, divers, etc.

Phil Rhodes
Video camera/edit
London


Phil Rhodes writes :

>>I believe PAG already have. Their tiny 10W light uses the same >topology as the Xenon HID headlamps,

Is this different from the Frezzi 10w MicroSun? They list it as a true HMI.

Mitch Gross
NYC DP


Phil Rhodes wrote:

>>...which makes them much more like HMI in mode of operation. Think >of them like an HMI with Xenon rather than mercury vapour fill.

'Splain the difference. One has fixed electrodes between which an arc is maintained in a xenon atmosphere, the other has fixed electrodes between which an arc is maintained in a basically mercury/bromine atmosphere. Seems like one is a xenon arc and the other is an HMI, and couldn't it be said that the HMI is like a xenon in mode of operation?

And does anyone really know what the HMI acronym actually stands for? I've seen, among other variations, "Helium Mercury Iodide" (Tech-Notes Glossary of Broadcast Terms) and "Mercury (Hg) Medium arc Iodide" (Carlson.)

Wade K. Ramsey, DP
Dept. of Cinema & Video Production
Bob Jones University
Greenville, SC 29614


>>And does anyone really know what the HMI acronym actually stands >for?

Hydrogium Medium-arc Iodide

Sam Wells


Hi,

>> Hydrogium Medium-arc Iodide

Gah, doesn't anyone do Latin at school anymore? Hg is mnemonic for "hydrargyrum," literally "water-like silver" since the Latin for silver is "argentum."

Hence the arcane description for mercury, "Quicksilver."

http://www.hyperdictionary.com/dictionary/hydrargyrum

Phil Rhodes
Video camera/edit
London


Here are some nice compact xenon arc lamps :

http://www.canimpex.ns.ca/XenonNews.html

http://www.hi-techlamps.com/analytical/ceramicx.shtml

http://www.artisan-scientific.com/48345.asp

Xenon lamps normally operate on direct current (DC), so a well-filtered power supply should produce little flicker.

Xenon lamps DO require high voltage ignition, and are under high pressure, and often have significant UV output, requiring proper safety procedures when handling and using.

Almost all theatres now use xenon arc lamp houses, rather than carbon arc.

John Pytlak
EI Customer Technical Services
Eastman Kodak Company
Rochester, New York 1650-1922 USA


Sorry it's been a long time since I took Latin.

Come to think of it, I never took Latin, that shows how long its been.

Sam Wells

...didn't look right either


Phil Rhodes wrote:

>>Gah, doesn't anyone do Latin at school anymore? Hg is mnemonic for >"hydrargyrum," literally "water-like silver" since the Latin for silver is >"argentum."

Sorry Geoff and all, I know this should be in chat by now, please allow me this... just once

Dear Phil,

I will copy form the link you just gave us:

Webster's 1913 Dictionary

Definition: \Hy*drar"gy*rum\, n. [NL., fr. L. hydrargyrus, Gr.
?; ? water + ? silver.] (Chem.) Quicksilver; mercury.

As you can see "hydrargyrum" comes from the Greek "hydrargyrus"

As a matter of fact :

"Hydor" is "Water" in ancient Greek. When used in complex words it becomes
"hydro".
"Argyros" is "Silver"
"Hydrargyros" is the silver that looks like water.

Nothing to do with Latin.

Regards

Argyris (yes it means "the man made of silver") Theos
DoP
Athens Greece


Hi,

>>Nothing to do with Latin.

Oh. Uh. Yeah. (Embarrassed shuffling.)

Well, it is practically identical in Latin!

Phil Rhodes
Video camera/edit
London



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