Heat and light

[Joshua_Putnam <josh@xxxxxxxxxxxx>]

I haven't scanned them in for my web page yet, but last night I
developed some interesting photos of bicycle frame brazing.  On
a shop tour I was taking plain old color photos of the
operations when I remembered that my OM-1 with HIE and an
internal 87 filter was out in my van, so I thought it was worth
playing with.

The lighting in the shop was fluorescent, so there was no
significant IR from the lighting, certainly nothing that would
make it through a no.87 filter.  I bracketed from f/2.8 to f/16,
all at 1/15 hand held.  As expected, the oxyacetylene flame is
bulletproof black on all the negatives.  On most of the smaller
apertures, that's all that came out.  On a few of the wider
apertures, however, the IR output of the flame illuminates the
surrounding frame tubes and the brazer's body, and a small area
of tubing around the brazed joint is also glowing.

It worked well enough I may decide to shoot some more views of
brazing using only the light of the flame the next time I get
around to brazing up a bicycle frame myself.  I figure I could
set up the tripod and use a bulb release with my foot so it
doesn't interfere with the brazing, and having the camera on a
tripod would avoid the visible shake in some of my hand-held 1/15
shots.

Anyone else do any IR photography of incandescent industrial
processes like brazing, welding, casting, etc?

-- 

 Josh@xxxxxxxxxxxx  is  Joshua Putnam / P.O. Box 13220 / Burton, WA 98013
                       "My other bike is a car."                   
                     http://www.wolfenet.com/~josh/
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