A comparison of fine grain
black & white film and digital images.
Except for artistic reasons,
when shooting film, most photographers are concerned about excess grain and try
to eliminate it as much as possible.
Unfortunately, that cannot be achieved all the time. It is an accepted fact of photographic life
that faster films do display more grain than their slower counterparts. Obviously, we have to match the films we
choose to the lighting conditions under which we take photographs.
Grain is also very closely
associated with sharpness and detail in a photograph. A coarse grain film simply cannot show as
much detail as a fine grain film. Fine
grain films are therefore inevitably sharper and for that reason more
desirable.
The slowest black & white
films on the market used to be Kodak Technical Pan, Agfapan APX 25, Efke KB 25
and Ilford Pan F. The Kodak Agfa and
Efke films had a standard rating of ISO 25, while the Ilford had a rating of ISO
50. All three of them were outstanding
examples of modern, fine grain films, and must be considered the best the
market had to offer.
Kodak Technical Pan basically
was a slow, high contrast film with extended red sensitivity, meant for copying
of documents etc. In the appropriate
developers, the film would display extremely high contrast as is necessary for
such work. However, when developed in
Kodak Technidol or similar developers, the film would display a continuous
tonal range with near normal contrast.
If we go strictly by published specs, there is nothing comparable on the
market. Technical Pan had finer grain
and a higher resolution than any other film readily available. This should make it the undisputed leader in
the fine grain film field.
Technical Pan could deliver
negatives of incredible sharpness.
However, since the film was basically a very high contrast material, it
did suffer from relatively high contrast, even when developed in
Technidol. When used in bright sunlight,
the results were fairly contrasty, too much so for a lot of photographers. The
film also had a low exposure latitude and required a very specific developing
procedures to make it useful as a standard, pictorial film material.
While the performance
potential of the film was unquestionably very high, it remained a special
purpose film with considerable limitations.
The Ilford Pan F is certainly
a tremendously capable film, but by virtue of its higher speed, it is not quite
capable to deliver the performance of the Kodak Technical Pan or that of the
Agfapan APX 25 and Efke KB 25. The
Ilford film therefore has to be considered to be on the bottom of this list.
As far as published
specifications go, the Agfapan APX 25 and Efke KB25 are not quite as sharp and
don’t have quite the fine grain of the Kodak Technical Pan. On the other hand, the films easily allow
adjustment of contrast by changes in exposure and development times. In addition, they do not require special
developers. Any good black & white
developer can do an outstanding job with these films. One such developer is Agfa Rodinal. Rodinal is not a particularly fine grain
developer, but it displays a very high acutance, which yields extremely sharp
negatives. Agfapan APX 25 and Efke KB
25, developed in Rodinal, have proven to deliver negatives of exceptionally
fine grain. Enlargements of 15 times
have proven to be virtually grainless, and even enlargements of 30 times are
still quite acceptable. Of course, this
is also very much dependent on the quality of the camera equipment.
The question is often asked
if APX 25 or Efke KB 25 couldn’t deliver even finer grain if a so called fine
grain developer was used. The answer is
certainly “yes.” But why? If 15 or 20 times enlargements from these
films, developed in Rodinal, show virtually no grain, why try to reduce grain
size? It wouldn’t make any visible
difference. However, the coarser grain
structure of high acutance developers usually renders a greater apparent
sharpness. A finer grain developer
therefore might have the effect of less apparent sharpness due to lower
acutance.
Reduction of development
times in Rodinal will lower the contrast of the negatives while an increase in
development time will result in the opposite.
In addition, the film can quite successfully be pushed to a rating of 50
and still yield very good results. The
film can also be pull processed at a rating of 20 or 15, to yield even finer
grain. This will also result in a
noticeable reduction of contrast.
It is this versatility which
ultimately made the Agfapan APX 25 and Efke KB 25 more desirable films than
Kodak Technical Pan. Given the right
lighting conditions, they are without question some of the best black &
white films ever made.
This photograph shows
approximately the entire negative area.
It was scanned from an
enlargement which was carefully adjusted
during printing to render an
exact 8X magnification.
This cropped section of the
original negative was scanned
from an enlargement, adjusted
during printing to be an
exact 16X enlargement
A section of the same 16X
enlargement, scanned from the original print.
This portion of the negative
was scanned from a 35X enlargement.
The very fine eye lashes in
the upper left corner have an approximate
Diameter of 0.007mm (0.00028
inch) on the negative which translates to a
resolution of over 140 lpm
(lines per millimeter) on the enlargement
which means that the on-film
resolution is even higher.
Unfortunately, the
overwhelming popularity of digital photography has influenced the photography
market to the extent that many films have been discontinued. Of the fine grain black & white films,
only the Ilford Pan F remains at the moment and therefore has to be considered
one of the best currently available.
Of course this brings up the
question if digital cameras are capable of delivering images of equal quality
and the answer is; definitely, providing we are talking of camera equipment and
especially lenses of equal quality. As a
matter of fact, given a sufficiently large sensor, especially full 35 mm frame
sensors with sufficient resolution, the same lenses might deliver even higher
quality images with a digital camera.
The limiting factor of
maximum resolution on film besides grain size is the fact that light will
scatter within the emulsion. This
definitely reduces overall resolution and it is the very reason why films will
never be capable of delivering all the resolution, all the detail that a high
quality lens is capable of. In
comparison, most digital sensors do not have this scatter effect, meaning that
a less quality reduced image can be produced.
Of course the ability of the digital camera system to suppress noise and
other image degrading phenomena are a factor also.
Following is a photograph
taken with a digital camera that shows that comparisons to even the best 35 mm
films present no problem. I purposely
chose the Leica Digilux 2 which has a modest resolution of only 5
megapixels. However, it should be noted
that compared to consumer cameras with similar resolution, the Leica Digilux 2
has a relatively large sensor that allows for larger individual pixels. The result is a higher image quality,
especially if the camera is used at lower exposure indices. It is obvious that in spite of the relatively
low resolution, the resulting images compare quite favorably with the above
black & white images taken with exceptional camera equipment and
exceptional film.
Image uncropped
Image cropped from a 27 x 36 inch full frame
image
The sharpness of the images
shown is such, that some of the small detail is so fine that it wouldn’t show
on an enlargement unless enlarged to approximately 16 x 20 inch. This is for instance the case with the above
black & white images. On an 8x10
enlargement, the very fine lashes are invisible.
Technical Data
Black & White Images
Camera: Leica
M3
Lens: 50mm Dual Range Summicron f/2
Film: Agfapan APX 25
Light Source: Broncolor
Impact with 25” soft light reflector
Developer: Agfa
Rodinal 1:100, 68ยบ F, 16 Minutes
Enlarger: Leitz
Focomat V35 with Leitz Focotar, 40mm f/2.8 and color head module
Technical Data
Color Images
Camera Leica
Digilux 2
Lens 7-22.5 (28 – 90 equiv.) Leica DC Vario-Summicron f/2 – 2.4
Exposure Index ISO
100
Light Source
Speedotron Brown Line
D402 and D802 both at 200 ws with umbrella and reflector fill
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I am amazed how well the Digilux 2 looks on these examples. After all, it is a relatively old digital camera. I would like to see the results of one of the current Leica cameras.
ReplyDeleteNothing I couldn't do with a Holga or Diana camera. Seriously, these results are quite impressive
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