Shiny metal

Images taken in a controlled environment or with a posed subject. All subject types.

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rjlittlefield
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Post by rjlittlefield »

Thanks for all the compliments and ideas, folks! :D

Congratulations, a round of applause, and a tip-o'-the-hat to g4lab, Stevie, and especially Planapo, who finally pulled together all the clues. \:D/ :smt038

Yes, this is the filament of a quartz-halogen automobile headlight. The one on the other side of my car burned out. When I replaced that one, I also retired this one, figuring it was probably past due anyway. Then of course, with a functioning but long-used bulb in hand, I just had to see what it looked like up close.

Viewing through the glass envelope was tantalizing but fruitless, so I scored and broke off the envelope. That left me with two bare filaments: one for the high beam that is seldom used, and one for the low beam that is on almost all the time.

Here is the pair:

Image

Shot through the 10X objective, with only a slight crop this time, the upper filament looks like this:

Image

Wikipedia has a good article about how these things work.

I haven't looked this close at other filaments, but I expect that the halogen cycle is critical to the appearance of this one. In a non-halogen incandescent bulb, tungsten atoms evaporate from the filament but never return, so there's not much opportunity for remodeling the surface. In a halogen bulb, tungsten is continuously scavenged from other parts of the bulb and returned to the filament by a set of reversible temperature-dependent physical and chemical reactions.

The process works great, and it sure does produce some interesting shapes, doesn't it?!

--Rik

Technical: Closeup shots using Canon 300D, Nikon CF N Plan Achro 10X NA 0.30 objective at nominal 150 mm extension, 34 frames at 0.0005" focus step, single electronic flash with pingpong and paper diffusers. Overview shot with Olympus 80 mm bellows lens, 10-frame stack at 0.010" step, dual fiber with only slight diffusion and a black backdrop.

Reference added 3/6/2022: https://physlab.org/wp-content/uploads/2016/03/Planck_ref8.pdf , "Basic Physics of the Incandescent Lamp (Lightbulb)", by Dan MacIsaac, Gary Kanner, and Graydon Anderson.

g4lab
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Post by g4lab »

Rik
I knew what I was looking at because I have seen such pictures before.

But none of them were as nicely done as yours! Very nice photos (as is usual)

rjlittlefield
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Post by rjlittlefield »

Ah yes, the power of experience -- things are so much easier to identify when you've actually seen them before!

Maybe we need a new saying: "A memory of a picture is worth a thousand searches." (Uh oh -- Google doesn't know that phrase! Did I just invent it??)

What surprised me was how difficult it was for me to find any similar sorts of pictures on the net, even knowing exactly what I was looking at. Granted, optical images at this resolution are difficult to shoot, but I figured the place would be swimming in appropriate SEM shots. It's not. Or if it is, I couldn't find the right pool.

In a quick scan, the best I could find were some pictures related to an undergraduate thesis, Case Study on Tungsten Filament Lamps, referenced HERE.

--Rik

Cyclops
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Post by Cyclops »

I missed this,fabulous stuff!
Canon 5D and 30D | Canon IXUS 265HS | Cosina 100mm f3.5 macro | EF 75-300 f4.5-5.6 USM III | EF 50 f1.8 II | Slik 88 tripod | Apex Practicioner monocular microscope

DavefromCt
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Post by DavefromCt »

The starter element in a fluorescent bulb?

rjlittlefield
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Post by rjlittlefield »

Dave, I think you missed the second page of the topic, where all was explained. It's an automobile headlamp, well used.

Lots of topics/threads here are like this one, with the discussion extending onto more pages. You have to look close, to find the "Goto page" links at the top left and bottom right of the page. Sometimes I miss them too.

But there's no problem with having revived an old thread. That happens a lot here. It's usually a good thing because it bumps some interesting image or discussion that the older members have forgotten and the newer ones haven't seen.

I am curious though. This topic would have been deep in the archives, almost 3 years old. Did you find it by rummaging through old posts, or see a link to it, or turn it up in searching, or...? Edit -- Ah, I see, followed a recent link in another thread. Question answered!

---Rik

abpho
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Post by abpho »

Nice work Rik.
I'm in Canada! Isn't that weird?

rjlittlefield
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Post by rjlittlefield »

Adding a bit of information and a link that I don't see appearing in this thread yet...

The images in this thread were made with Zerene Stacker DMap, back before it was publicly available.

I have since reprocessed the stack to produce a stereo pair also. That can be seen HERE.

--Rik

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