Re: [APML] Films responding to Ha, Hb, OIII

["Stuart Heggie" <stuart.j.heggie@sympatico.ca>]

Ray, this is very interesting to me. I recently bought 3 rolls of Kodak Chromogenic film - I was
really pleased with how it performed in daylight and the C41 processing was a big bonus (I have put
away my darkroom toys a long time ago). I tried it for star trails and it was a bust. How sure are
you that it will work for long exposure? I think it would be great if there were a C41 compatible
B&W film.

Stuart
----- Original Message -----
From: "Ray Butler" <ray.butler@nuigalway.ie>
To: "Michael Barlow" <mikeba@rochester.rr.com>; "Discussion of Film Astrophotography"
<astro-photo@seds.org>
Sent: Tuesday, October 12, 2004 2:34 PM
Subject: Re: [APML] Films responding to Ha, Hb, OIII


>
> And welcome from me too, Michael.
>
> You might also consider that since most colour print films are pretty
> dead to H-alpha, and poor enough in the blue-green region of H-beta and
> OIII, another alternative with a nebula filter is to use black and white
> film. This will perform really well on H-beta and OIII because it
> doesn't have the "falling between two stools" sensitivity problem that
> colour films (both prints + slides) have in this part of the spectrum,
> where their blue and green curves dip and cross over each other.
>
> There is a tradeoff, which is that you can't expect to pick up much or
> any H-alpha (unless you use some hypered Tech Pan, while it's still
> available). But for the filtered H-beta->OIII region (which is so narrow
> that a monochrome film is most appropriate anyway), B&W is ideal.
>
> And if you use a C41-process "chromogenic" B&W film, you can have your
> film processed anywhere that develops colour print film. Kodak TC400N is
> probably the best choice since it has extremely good reciprocity
> characteristics, according to Michael Covington's tests. Apparently it
> is now renamed Portra B&W or Kodak B&W. As always, check the film's
> spectral sensitivity curves on the spec sheets first. Here are the Kodak
> B&W specs (which look fine for H-beta->OIII):
> http://www.kodak.com/global/en/consumer/products/techInfo/f15/f15.shtml
>
> Ray "testing this film soon" Butler
>
>
> Michael Barlow wrote:
>
> > Hey gang, I'm new to the list,
> >
> >     I've been photographing nearly two years but have never got in to the
> > technical side of it.  All I've been doing is grabbing film off the shelf
> > (color print film) at the local grocery store and department stores for
> > Lunar, Planetary, and white light Solar through my 8" SCT.  Just the last
> > couple weeks I've been grabbing shots of M31, M45, and snapping away at what
> > ever else I happen to see and wanted to step in to filtered photo's such as
> > Ha, Hb, OIII, and ect...  I just bought a Meade #911 Nebular filter for the
> > SCT and just learned that most films have been reformatted to virtually
> > eliminate responses from Ha but haven't heard anything about the other two,
> > Hb, OIII.  For the beginner in the filtered end of photographing in one or
> > all the above frequencies, Is there a cheap 35mm film that responds well
> > enough to learn from, color or B/W?  I.E. Until I get my feet wet I'd rather
> > not buy expensive Hypered film or anything that costs over $5 US per roll.
> >
> > Michael A. Barlow
> >
> > _______________________________________________
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> > Astro-Photo@seds.org
> > http://seds.org/mailman/listinfo/astro-photo
>
> --
> Dr. Ray Butler (ray.butler@nuigalway.ie || ray@physics.nuigalway.ie)
> Lecturer, Dept. of Physics || Computational Astrophysics Laboratory
> National University of Ireland, Galway, University Road, Galway, Ireland.
> Tel: +353-91-524411 ext. 3788   FAX: +353-91-525700
>
>
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