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

[Ray Butler <ray.butler@nuigalway.ie>]

Stuart,

> 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. 

Sorry: in American slang, does "a bust" mean a good or a bad result? I'm 
wondering, since "Hollywood, or bust" means "failure" whereas the 
similar term "having a blast" means "absolutely great"! It's not a term 
which has crossed the pond yet...

 > How sure are you that it will work for long exposure?

I based this on Michael Covington's
http://www.covingtoninnovations.com/astro/updates.html
and
http://www.covingtoninnovations.com/astro/films.html
- which was "Revised 2003 October 24", so it should still be applicable;
and on Patrick Freeman's 
http://www.geocities.com/freeman_patrick/astro_film_tests.html
- whose conclusions (on the chromogenic films) I don't at all agree 
with. What he calls "saturated" I call "actually picking up lots of 
light and having the lowest reciprocity failure" ! To me, T400CN clearly 
comes out best of the lot (and somewhat better than the identical 
pairing of Portra B&W/Select B&W+), although to him it was the worst. 
And he reckons the XP2 Super was best, whereas to me it is clearly the 
least sensitive. So we take polar opposite views, based on these images. 
Anyone else care to comment?

Ray

> 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
>>>
>>>_______________________________________________
>>>Astro-Photo mailing list
>>>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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>>http://seds.org/mailman/listinfo/astro-photo
>>
> 
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-- 
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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