Re: [APML] Print films for AP

["John C. Mirtle" <jmirtle@shaw.ca>]

Nicola,
    You might want to stay with the E200 or Provia. I have shot some B/W
(Tri-X), have a look at http://members.shaw.ca/john.mirtle/files/m78.jpg .
It was taken with a cold camera, for 30 minutes at f11 on a C14. This is a
full-frame scan, you can see how grainy Tri-X is when processed in D-19. One
BIG problem with Tri-X is that it has no sensitivity to H-alpha. This means
that it is no good for tri-colour.
    By far the best B/W for tri-color is tech pan, and it must be hypered. I
have done a few shots using Wratten filters for colour separation, and even
with a Schmidt camera at f1.5, exposure times for 2 filters are an hour or
more. At f3 you need to quadruple the exposure times, I'm sure you can do
the math! Another option for tri-color at slower f-ratios is custom filters
with higher throughput, Chuck has some experience with this. They cost a bit
though.
    Tri-colour is tough, but the results are awesome. Not too many people
are doing it, but check out web sites of Loke Tan, Chuck Vaughn, Chris Schur
and the Schmidt pages on my web site. You really do want to think twice
about this! E200 and Provia are a lot easier....

John Mirtle
Calgary, Ab. Canada
http://members.shaw.ca/jmirtle

----- Original Message -----

Don,

I had a look at Robert Reeves' page, and he mentions Ilford HP5+ as a good
candidate, but actually I didn't see any of you using it. Well, in reality
since I subscribed to APML I can't recall of any B&W picture, but I might be
wrong.
For the people using negatives, after supra 400 passed away, it could be a
good time to turn back to B&W and tricolor photography...but this is only a
guess as I never used (up to now) B&W myself.

Is there any tri-color film astrophotography homepage that I could look to
get hints of where to start (for instance, which filters for LRGB? How much
should I expose each color? and so on...)

Regards,
Nicola
http://astrofoto.laza.it


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