Talk:Headlamp

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France, yellow and halogen

(Transfered form [Talk:DieSwartzPunkt] where it was incorrectly posted.)

Your assertions about halogen headlamps being unavailable for use in France because of that country's requirement for Selective yellow light were unsupportable because they were wholly incorrect. In fact, a great deal of the development work and initial commercialization of halogen headlamps took place in France. Yellow glass lenses, yellow reflector coatings, and yellow internal filters covering the bulb were among the techniques used to obtain the required yellow light color in conjunction with a colorless halogen bulb. Please refrain from inserting guesses and assumptions into articles, won't you? Thanks. —Scheinwerfermann ^T·_C19:30, 17 May 2012 (UTC)

Whilst I take your point about development work involving yellow internal filters, reflector coatings etc. etc., French law, at the time of yellow headlights specifically required that it was the bulb itself that had to be yellow. A yellow coloured glass front, although it would achieve the same effect, was not actually legal. I have little doubt that had France accepted a method of facilitating, selective yellow headlights using halogen bulbs, they may well have ammended the legislation. Many visitors to France would either fit yellow filters in front of the headlight or even coat the glass with a yellow varnish. Although complying with the spirit of the requirement, such a measure did not meet the letter of the law. This last point is entirely moot however, because non French registered vehicles were exempt from the requirement anyway. DieSwartzPunkt (talk) 11:31, 18 May 2012 (UTC)

First off, my request that you refrain from inserting your own guesses and assumptions into articles was not "incorrectly" posted on your talk page. I put it there on purpose, since your history gives the appearance that you've done this before on other articles. Evidently you do not "take my point"; your summary of it is not accurate. Your assertion that French law required the bulb (specifically) to be yellow is not factual, never was, and will remain untrue no matter how often you wish to repeat it. The requirement was for selective-yellow light to be emitted from all road illumination devices (headlamps, fog lamps, driving lamps). Across the whole duration of its force from 1936 to 1993, French regulations never specified or constrained the method by which compliance was achieved. Yellow bulbs were the most common solution prior to the launch of halogen bulbs, because that was the cheapest and easiest solution. However, yellow bulbs were never the only solution, even before the advent of halogen lamps.

There were other unsupported (because unsupportable) guesses and suppositions in the text you inserted and I removed; I suppose you can be disabused of them one at a time here on the talk page if you insist. In the meantime, I note from your first draft of your rebuttal that your assertions regarding the (nonexistent) French requirement for a yellow bulb are based on what you seem to think you remember having been "advised" (i.e., told) by persons unknown sometime in the past. Until you provide the reliably sourced "letter of the law" you seem to think you understand, we can probably go ahead and adjourn this conversation for now. —Scheinwerfermann ^T·_C22:27, 19 May 2012 (UTC)

It was incorrectly posted to my talk page because it was a discussion about article content. As for, "since your history gives the appearance that you've done this before" means that it is you that are now guessing. DieSwartzPunkt (talk) 12:40, 23 May 2012 (UTC)

Talking of guesses and supposition, where is your evidence that the requirement was simply for a yellow headlight? All the years that I travelled and worked in France, I never saw a yellow headlight on a French car that was not achieved using a yellow coloured bulb. Thus, the premise that it had to be the bulb was not unreasonable. In fact, I never saw a halogen bulbed headlight on any yellow headlighted car. 212.183.140.52 (talk) 12:40, 24 May 2012 (UTC)

I didn't attempt to put unsupported assertions in the article, so I face no burden of proof here. Nevertheless, I'll go ahead and do DieSwartzPunk's homework for him/her and prove you wrong while I'm at it. While your "I don't think I remember ever having seen it, therefore it doesn't exist" approach to the matter falls well short of WP:RS, fortunately there are plenty of WP:RS sources that refute your and DieSwartzPunk's guesses, assumptions, and vague recollections; one of them is this technical paper published in 1970 by the Society of Automotive Engineers. My copy of it was a little over three feet from where I presently sit typing until I got it off the shelf to remind myself of its paper number so I could provide the link.

Now then, I'll also be happy to broaden your horizons by showing you some of those yellow halogen headlamps you think don't exist. See here (Marchal Amplilux units, which take an H1 low beam bulb—go read the H1 article to learn what the "H" stands for—and an H3 high beam bulb, with yellow lenses; more photos and description here), here (another variety of Amplilux, this one with yellow glass filters as a permanent part of the headlamp located over the H1/H3 bulbs; see also here), here (Cibié "Biode" units with permanent yellow glass filters, clearly marked as taking 55w H1 bulbs), here (a Cibié H1 high beam with internal yellow filter, here (same H1 lamp but with yellow lens), here (the matching Cibié H4 lamp with yellow lens), here (Hella low and high beam H1 headlamps with yellow lenses), here (Cibié type 45 fog lamp with H1 bulb and yellow lens), here (BMW E21 3-series yellow-lens halogen headlamps, new in the box), here (Bosch yellow-lens driving lamps, new in box, with H1 bulb seat clearly visible through lens), here and here (two different kinds of original-equipment BMW E36 3-series headlamp with yellow internal optic lenses…first year for the E36 was 1992; nobody was using non-halogen bulbs by then), here (Carello halogen low and high beam headlamps with yellow lenses), here (BMW E30 3-series halogen headlamp with yellow glass lenses…go on, dare to zoom in on the photo and if your monitor is any good you can clearly see the "HC" and "HR" function codes on the low and high beam lenses respectively. You may not know that the "C" is for "Code" which means "low beam" and the "R" is for "Route" which means "high beam", but I bet you can guess what the "H" stands for if you put your thinking cap on). And look over here! It's a new-in-the-box yellow glass lens for Porsche 911 H4 headlamps. There's that pesky "H" again! Post number 6 on this page shows a photo of the earlier twin-reflector/twin-H1-bulb version of that yellow-lens Porsche 911 headlamp, and another set of them can be seen here. Then there's this Mercedes headlamp assembly equipped with Bosch yellow-lens halogen H1 low and high beam lamp units, and I count five different yellow halogen fog lamps here, one of which can be seen removed from its housing here (H'mm…H2 bulb aperture clearly visible on the back, covered by a protective shipping cap…h'mm, yellow filter clearly visible through the lens despite absence of a bulb!). And here is a new-in-box pair of Hella fog lamps with H1 bulbs and yellow lenses. Here is a set of inboard (high beam) headlamps for a French-spec VW Golf/Jetta…gosh, lookit there, it's yet another one with halogen bulbs and yellow internal filters. And here is a seldom-seen (but stubbornly existent!) pair of early-1990s Valeo H1 low beam headlamps with yellow lenses. I could go on (and on and on, as you can see) but I do believe I've probably gone a reasonable distance towards making my point and breaking yours. —Scheinwerfermann ^T·_C20:02, 24 May 2012 (UTC)

You may not have made the assertion, but once you reverted the content, you became liable to support what you restored (WP:BURDEN as you are obviously unfamiliar with it). All the above was a complete waste of typing because it is entirely original research. A list of examples proves nothing. You need to cite a verifiable source (WP:VERIFY ). I should have guessed from the manner of your previous post that you were an 'anoroak'. Still, at least you have proved that you don't know everything, because you obviously know fuck all about indenting properly. Don't correct my comments in future if you don't know what you are doing. I was replying to you and not to Dieswartzpunkt as you made it look. .I have corrected my post and indented yours correctly as well (because, unlike you, I do know what I am doing). 212.183.128.193 (talk) 11:32, 25 May 2012 (UTC)

Good heavens, your reading comprehension is atrocious.—Scheinwerfermann ^T·_C23:17, 25 May 2012 (UTC)

Headlamp lens material

Hello, I have observed that since this century turned, new cars have had headlamp lenses made out of plastic. Before headlamp lenses were made out of thick glass that reminded me of Pyrex cooking vessels intended for use inside an oven. Is it true that it was in fact heat-resistant borosilicate glass? What is the plastic in use nowadays? I suppose it is polycarbonate plastic, but is it regular or somehow treated or coated? I would answers to these questions in the article. Also, were the transition to plastic lenses possible only after halogen lamps became history? I believe that halogen lamps emitted so much that heat that polycarbonate would have melted. So, if the transition was only possible because of technological development in lamps, and a consequence of this, please point it out in the article. --91.157.12.243 (talk) 13:16, 21 September 2012 (UTC)