Personality is Everything!

When you say "I like film X!", or "I don't like film Y!", you are probably reacting to the "personality" of the film and how it behaves in the type of scene you are trying to interpret.

Although the personality of the film may transcend film size and format, the criteria used to select film for medium or large format cameras does differ from those used to select film for a 35mm camera or Minox. Added to the complexity is that the film of choice may not be available in the desired format. When assessing a film's applicability, one must consider the -

Your negative is rarely if ever seen, so unless the goal is to demonstrate the virtues of specific equipment or methods, neither equipment or method is of interest to the viewer and should never be an excuse for anything but the best result. Each film, modified by the way it reacts to variations in development, possesses a set of characteristics, the sum of which form its personality. The shape of the characteristic curve of a film is, along with the film's speed, granularity, resolving power, and spectral response, fixed by the makeup of the emulsion. Of all of these characteristics, it is the characteristic curve, the film's response to variations in luminance, that is most influential in how the final print will appear.

The illustration shows, two films with the same luminance range, Zone I density or "film speed", and when developed properly, similar Zone VIII densities. But, as the curves show, they react to the intermediate light values in entirely different ways. Short toe films react quickly to differences in low light, essentially building density quickly as the light increases. Long toe films take more energy to activate and show increased density much more gradually. As the graph illustrates, it takes considerably more exposure to reach a given density with a long toe film.

For example, if a density of 0.3 above film base plus fog is needed to provide desired shadow detail, the appropriate scene values may be placed on Zone II with the short toe film, but must be placed on Zone III with the other. In fact, throughout much of the midtones range, more exposure is required for the long toe film. BUT, the real difference is in the visual differences in both the negative and the final print. The short toe film records better separation in the low values, while better high value separation is provided by the long toe film. The difference can be dramatic and accounts for many of the expressed preferences for one film over another. In reality, each has a place in the photographer's bag.

Different Films, Different Developers!

I have experimented with a number of films, for use with 120, 35mm, and Minox 8x11mm cameras. Each has a distinct personality, with assets and liabilities. Often the difference is purely subjective and best described by "I like it!", or "I don't like it." The acceptability of a given film is dependent on a number of factors, perhaps the most important of which are the photographers vision and threshold of acceptability.

Remember that these are MY results, with MY equipment, and MY procedures, AND MY EXPECTATIONS. Your results WILL be different.

I generally develop film with either Rodinal or PMK Pyro, each of which produces negatives expressively and physically different from the other. So, with the variables of scene luminance and film selection, as well as choices of developer, dilution, and development time, the possibilities are endless - and that's what makes it FUN!

Several of the films popular in recent years for subminiature photography -

For the chart below, a Minox LX was used to compare the four films. Successive exposures were made providing the required EV values with a Kodak Gray (& white) Card in various positions in shade and sunlight.

Corresponding shutter speeds were chosen to produce Zone values from -3 to XII for a nominal film speed of ASA 30, as measured with my Pentax Digital Spot Meter. Thus the Zone V Minox exposure was made when the gray card was positioned to give an EV value of 10.5 and the shutter speed set at 1/30 second. The rightmost part of the table is for reference only and is my standard for testing 35mm film in a Nikon FE

The four rolls were identically developed at 20 deg. C., according to my standard Rodinal procedure.

Since my definition of "film speed" (my EI, "Exposure Index") is a density of 0.1 above film base plus fog at Zone I, and since these curves were gathered expecting the film had a speed of ASA 30, a rough estimate of the actual film speed (under MY conditions) can be had by shifting the curve to the left until it contacts the intersection of the Zone I vertical line and the 0.1 density horizontal line. Cutting the film speed in half for each "Zone" the curve is shifted to the left, I have an estimate of MY exposure index.

The table below shows the Exposure Value (personal ASA) values I have established as a result of "film speed" tests to establish a Zone I density of 0.1 above film base plus fog. I find that setting my automatic exposure Minox C at double the "actual" speed provides the best overall exposure in a variety of situations. Your values WILL vary, depending on more factors than I can name, and should be established by you personally.

FILM

Actual "Zone I" EV

"Automatic Camera" ASA Setting

Tech Pan

25

50

Fuji HS-U

12

25

Agfa Copex Rapid

6

12

Fuji Super HR

3

6

The shapes of the curves provide information about what to expect and, in my view, define the "personalities" of the films. Tech Pan and Fuji HS-U, for example, might provide similar densities with scenes having limited shadow detail as at the sea or airport. If the HS-U curve proves to be accurate, the very short toe might have application where low value local contrast is important. Prints from Tech Pan and HS-U have a significantly different appearance due, I suspect, to the extended red sensitivity of Tech Pan.

Although I used Rodinal and sodium sulfite for these comparisons, other developers and/or other development procedures will give different results.

Four rolls of Kodak Tech Pan film, were identically exposed using an ASA (ISO) rating of 25. They were developed in four different developers, using the manufacturers recommendations for TD-3 and Technidol LC, and my personal procedure for Rodinal. The process was not replicated, nor was an attempt made to adjust the procedures to "match" the curves at either Zone V or VIII. The only concern was with the shape of the curve in the area of the toe and how it affected the point at which the curve crossed the 0.1 density line.

The actual film speed may be estimated by judging how far its curve must be moved right or left until it crosses the 0.1 density line. Thus the green curve must be moved to the left approximately 2/3 of a Zone, resulting an ASA 2/3 of a stop slower than ASA 25 (ASA 15.7).

The effect of sodium sulfite on Rodinal is nearly a half stop increase in film speed (defined as requiring a film density of 0.1 above fb+f (film base plus fog) at Zone I), although the densities are similar in the area of Zone V. The difference between the curves at Zones I, II, and III is significant and, depending on the photographer's understanding of the characteristic curve, is the difference between the presence and absence of good shadow detail. Since I have not attempted to adjust development times and agitation routine, limited assumptions about the value of the various developers should be made. Suffice to say that the shape of the curve can have a profound effect on the metering and exposure of low values, and on the amount of shadow detail and local contrast captured.

Which one(s) do I like? All of them! Each has a personality different from the others, providing a choice of "canvas" on which to paint. But, if the combinations of film and developer provide nearly infinite variability, imagine the added opportunities when including the combinations of printing paper and developer!

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