Re: [APML]: 37 films tested (was Gold Max)

[Robert Reeves <rreeves@connecti.com>]

Hmmm....

I guess my last message with this topic header didn't make too much sense
because it was an addition to a message that didn't get posted.  Let me
insert the whole thing.

>While we are on the topic of films, has anyone tried Kodak Gold 
>MAX?? So far is seems to be a nice film... Any thoughts appreciated.
>---------------
>Dr. Scott Teare
>University of Illinois and Mt. Wilson Observatory
>Mt Wilson, California.

Well...as long as we are on the subject, I have recently tested 39 UNHYPERED
films (37 actually, two are not made anymore) for reciprocity loss and color
shift.  I didn't mean to make the test a Fuji vrs Kodak war, but that is all
that is available is this one-horse town.  I could get Ilford B&W, but no
Ilford or Agfa color film.

I exposed them between 2 and 8 minutes (depending on the film and how lazy I
was) to measure reciprocity and 2 minutes on an LED test setup to see how
each film responded in blue, green, and red.  The data is ONLY relative to
comparing one film to another with my test set up.  No specific scientific
numeric data can be inferred from these tests.  The main thing is that all
films were exposed equally so you can see that film A is better/worse than
film B, etc.  So when looking at the data all together, you can conclude
which film hold the best promise for further star testing under the rather
limited clear dark sky we can get.

To get to the short of it, Gold Max is pretty rotten astrofilm.  I has a two
f/stop speed loss within the first two minutes of exposure, and goes down
hill from there.  The blue sensitivity isn't so hot and the red responce is
less than other off-the-shelf films.  Off the top of my head, I would rate
(UNHYPERED) Royal Gold 1000, PJ400, PJC-1, PMZ, and Fuji Super G 100 as
better unhypered films for long exposure wide-aperture work.

I was going to get all this test data on my web site (B&W, color neg, and
slides) before mentioning this, but the discussion theard seems ripe now.
I'll have the rest of the film tests on my web site in about a week so all
films can be looked at.

The LEDs were a generic blue, generic green, and a 660 nanometer red LED.  I
have no idea what wavelength the blue and green LEDs are, but I made sure
the red one just beyond the H-Alpha for obvious reasons.

What all that mess boiled down to is that out of 15 color negative films
that I can get my hands on easily here in my hometown, five stand out as
having good long exposure responce in all three blue, green and red colors.
These seem like the ones worth fooling with on those rare clear moonless
nights when you can get outta town.

They are in order of my preference:

Kodak Royal Gold 1000    (One stop speed loss in two minutes)
Kodak PJ400              (2/3 stop   "        "       "     )
Kodak PMZ                (1/2 stop   "        "       "     )
Kodak PJC-1              (One stop   "        "       "     )
Fuji Super G 100         (1/3 stop   "        "       "     )

Grain was not considered because compared to the 40-grit sandpaper we used
to use as astrofilm, all films are fine grained.

Now I'll sit back and let the fur fly.  I'm sure folks have their favorites
that they will deffend and I am open to "reeducation" if there is a fatal
under-the -stars flaw with one of these films.
Robert Reeves                Home page http://www.connecti.com/~rreeves
520 Rittiman Rd.             Email     rreeves@connecti.com
San Antonio, Texas  78209    Phone     210-828-9036
                             Location 29.484N  98.440W  200 meters