FIRST REPORT ON EKTAR FILMS

In this second lecture in the series on Ektar films, we will cover
a film that first was not very promising, yet in the end surprised
us all with its fine resolution and good neutral color balance. 
And next, a film that will be of definite value with the upcomming
Comet Austin.  Its high speed, finer grain and supurb blue response
will make it a top choice.

Ektar 125

Our first impressions with this film were less than ideal.  Despite
being a sister emulsion to the 25 ISO film, its characteristics are
very different.  The film was evaluated in the same way as the
Ektar 25, first with a 50mm f/1.4 lens piggy back, and with
exposures up to 32 minutes duration.  Much to our surprise, the
hypering time was less, about 12 hours to yield the proper hyper
fog density.  An eight minute exposure gave the best image density
on the same Cassiopiea star field.  This translates to a speed
increase that was less than the Ektar 25, despite the same hyper
fog levels.  It was noticed also that the films contrast and red
sensitivity were very low only showing a trace of emission
nebulosity in the constellation.
  
The schmidt and telephoto tests proceeded using 8 minute exposures
for the schmidt camera, and 30 minute exposures for a 135mm f/2.8
telephoto lens.  As expected, the North American Nebula looked pale
and tepid, and the nebulosity in the Pleiades was nearly non
existent.  However, shots of the Orion Nebula (M42) and the
Andromeda Spiral (M31)  did not burn out the cores like the 25 ISO
emulsion and gave an overall more pleasing image.  The low contrast
of this emulsion suggested that it might be a suitable film for
lunar work, in which the normal and high contrast films only record
a narrow region of brightness on the terminator.

With this in mind, a number of us tried prime focus and projection
lunar photography with surprisingly good results.  The extended
exposure latitude did indeed increase the detail visible on the
terminator, without having to overexpose the rest of the lunar
disk.  The films fine grain compares very favorably with the
extremely fine grained black and white 2415 emulsion, which is the
mainstay of many lunar photographers, and its neutral color
characteristics yielded many finely detailed creamy white colored
lunar images, (except for the underexposed images which had a
slightly greenish tint) with a high degree of resolution and
detail.  

Ektar 1000

High film speed is generally associated with large grain size and
poorly resolved images.  We found that Kodak has made great strides
in film technology since the days of VR1000.  The grain size and
structure of this new film is much better than Kodaks previous high
speed films which lends itself to better detail and resolution in
the final print.  The color sensitivity of this emulsion is
unusual.   Although Ektar 1000 has only moderate red sensitivity,
it has among the highest sensitivities in the blue end of the
spectrum of any film we have tried.  This translates into one of
the best all around films for work with galaxies, reflection nebula
and star clusters.  

In our initial testing with this film, a 14" f/5 newtonian was used
along with a variety of exposures on The Orion Nebula, NGC1973/77
just to the north, M41 in Canis Major, and M65/66 in Leo.  The
films unusual color sensitivity was first realized in the Orion
Nebula shot.  The nebula was primarily blue in color, with a
lavender ring of nebulosity surrounding the outer core.  Since the
blue component of M42 is caused primarily by the light of hydrogen
beta line, there was plenty of nebulosity over the entire field. 
The high blue sensitivity of this emulsion brought out a tremendous
amount of detail and nebulosity in NGC1973/77.  This nebula
photographs as a beautiful sky blue color, studded with brilliant
white stellar gems throughout.  The good contrast of this film also
revealed much internal detail in the form of dark nebula and rifts.

The performance on open clusters such as M41 in Canis Major was
stunning.  Hundreds of stars were recorded in short exposure times
each with thier own subtle colors and brightness.  The fine grain
of this emulsion would make it very suitable for well resolved
shots of globular clusters and rich open clusters.  

Galaxies also record very well with this fine grained and clearly
blue sensitive emulsion.  M66 showed delicate internal details in
its spiral arms such as knots and dark lanes, while M65 clearly
revealed its sharp stellar core and dark equatorial dust ridge. 
Such details in a mere 20 minutes of exposure makes this film a
real winner for surveying the several hundred of the brightest
galaxies, scores of reflection nebulas, and countless globular and
open clusters in a relatively short time.