Re: Colored sparks (photography) (fwd)

---------- Forwarded message ----------
Date: Mon, 15 Dec 1997 12:51:48 -0500 (EST)
From: Wes A Brzozowski <wesb-at-blue.spectra-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Colored sparks (photography)

On Sun, 14 Dec 1997, Tesla List wrote:

> From: 	Gary Lau  14-Dec-1997 1948[SMTP:lau-at-hdecad.ENET.dec-dot-com]
> Sent: 	Sunday, December 14, 1997 6:35 PM
> To: 	tesla-at-pupman-dot-com
> Subject: 	Re: Colored sparks (photography)
> I shot a roll of film on my coil.  While most of the shots were the
> normal time exposures of the sparks, I was especially anxious to see
> photos of the brilliant yellow sparks I had produced with table salt.
> Upon getting the prints back, the normal shots came out super, but I was
> utterly disappointed in the yellow spark shots.  The arcs were all
> properly exposed, but their color showed absolutely nothing different
> from the normal sparks.  It's like I was photographing ghosts!  How could
> visual and photographic perception be so different?
> FWIW, I was using ASA200 Kodacolor print film, between /f2.0 and /f2.8.
> Between 5-8 second exposure times produced some real nice shots.

This is exactly the result commonly gotten when photographing
pyrotechnics. There are a number of reasons, as well as things to do to
fix the problem. Unfortunately, not being much of a photography buff, 
I've never really paid attention to the discussions I've heard on the
subject. But I do have a pointer for some information: there are always
a few heavily experienced pyrotechnic hobbyists hanging out on the
rec.pyrotechnics newsgroup, mostly just trying to keep the kids there 
from hurting themselves. They appreciate the more rational questions
like the one your problem poses, and they can either answer your 
question, or guide you to people who've already solved a problem which 
may be very much like the one you're experiencing.

Best of luck, and let us know how it goes...

Wes B.

* wesb-at-spectra-dot-net *       "It's a magical world, Hobbes ol' buddy...       *
*                  *          ..Let's go exploring."     - Calvin           *