[APML]: Re: [APML] astrophotography

[byen@ix.netcom.com]

Mike Regish wrote:
> 
> >  With the newer color films exhibiting excellent
> >reciprocity characteristics (Kodak PPF400 or Fuji SG800: 5-7 min @f2.8, 15 min
> >@f4), I don't think you even need to bother with the hassle of hypering
> (unless
> >you're using a slow system, f8 or beyond).
> 
>         Is the Kodak color film PPF 400 or PPF 2 400? I thought I'd seen
> references to PPF 2 somewhere. I have some PPF400, but I don't do color in
> the lab yet.

 By "PPF 400", I'm using the general designation (like on the film box or canister).  
On the film, you will see PPF-2 inscribed near the sprockets.  So, you're talking 
about the same.

> 
> >Kodak PPF400 seem to give better results (more contrast).  He had previously
> >said the blue response "took off" after hypering.  He is going to (or already
> >has) try it out with his f7 system (70min exposure).  B. Fletcher has
> >communicated to me, that hypering PPF may not be desirable.
> 
>         Hmmm...

Note the recent photo in Astronomy by B. Fletcher (8" Schmidt Camera, Hale-Bopp & 
deep sky object); he was using hypered Kodak Gold 100.  I heard someone on APML was 
experimenting with this.  Now, for ASA 100, I would expect that hypering IS pretty 
much a necessity.

> 
>         Another thing I've been wondering (I should probably start a new
> thread here)...I just shot a roll of unhypered Tech Pan in daylight at ASA
> 125 and developed it in D76 for a contrast index of 2.1, and it was *very*
> contrasty. Is D19 necessary for developing hypered Tech Pan or is it just to
> get the maximum contrast? It seems like for some nebulae one might want a
> little lower contrast level. I guess I'm just wondering if D19 is *always*
> the best way to go, or if there might be objects that do better with
> different developers and/or contrast levels?

  Another friend with 8" f1.5 Schmidt Camera just tried HC110 dilution B, and was 
raving about it (gradual tonal variations, rather than "blocking up" in bright 
areas).   Apparently, this is being used by some people (I remember some guy in 
Australia recommended it, in sci.astro.amateur back in March).  I almost gave it a 
go myself, a week ago.  Probably will try it next time.