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Re: (meteorobs) OT: Film for comet photos

Regarding color balance, this may have been an issue in the past,
but these days with most photos prepared in digital form for posting
on websites and so on, the overall color balance of a particular film
is largely irrelevant. Most image processing application, like
Photoshop for instance, allows you to adjust the various color
levels to achieve basically a perfect balance from any raw image,
as well as enhance every subtle detail.

The real issue is to choose a film with very fine grain, high
resolution and good reciprocity characteristics. One such film is
Kodak Royal Gold 200. The 400 speed version is grainier, but still
can be enhanced to yield a decent image. You can see my result
with this film of the Comet LINEAR at:

http://www.qsldot net/ah6l/A2_image.html

Its a 5min exposure with normal 50mm lens and shows about 8° of
tail after processing in Photoshop. The raw image is pretty cruddy,
I can email it to anyone interested in the comparison!

Mike Linnolt
Hawaiian Astronomical Society


On 9 Jul 2001, at 23:37, C.L. Hall wrote:

> >What is the high speed tungsten film that you use???
>
> Kodak Ektachrome 320T.
>
> It's a colour slide film, balanced for tungsten light as opposed to
> daylight.  It is not recommended for meteor work - most meteor work tends
> to be black and white.  It is also not recommended for comet shots if you
> want what people accept as realistic colour.
>
> Tungsten film is great for copying prints.   Having some in the fridge a
> number of years back, I decided to try it for astro shots, and found that
> it tends to work very well for comets.  If you are near a city, it changes
> the sky tones to blue, and eliminates the awful green and brown skies of
> light polluted areas.  It tones down moonlight.  It brings out comet tails
> very nicely, and will pick up tail in situations where daylight films have
> problems.  The tungsten film is also much more forgiving as regards sky
> fogging.  With that said, for major comets I will run a number of types of
> film, both daylight and tungsten balanced.
>
> I don't use filters.  I just enjoy pushing the limits of obscure types of
> film - and comets are one of my favorite subjects.
>
> Clear skies,
> - Cathy Hall
>    south of Ottawa, Canada

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