When it comes to selecting and using black-and-white developers, many photographers are like timid diners: they would rather be "safe than sorry!" Instead of adventuring into the realm of untried cuisines they always opt for familiar old favorites. Granted, the range of possible choices among B&W film developers is bewildering, akin to the diversity of different dishes you might encounter at a large buffet. But if you approach the problem like a good chef systematically planning a meal, most of the pitfalls of blind adventurism can be avoided.
Let's consider, for instance, a "meat and potatoes" approach, like using D-76 to develop Tri-X. It's a safe bet that the results will be just what you expect, but under certain situations it may fail to satisfy the requirements of a more sophisticated palate. Carrying the food analogy a step further, to make a good meal, the main dishes must be compatible. An awareness of the characteristics of different developers and types of film makes obvious the incompatibility of certain combinations -- like pickles and ice cream! Just as champagne and caviar are appropriate only for special occasions, certain film/developer combinations are ideal for some applications but wholly unsuited to others. Panatomic-X developed in Microdol-X, for example, would not serve a photojournalist very effectively, but would be highly appropriate for a landscape photographer making mural-sized prints.
Though the basic principle of bringing together complementary and harmonious elements is the same, making developer selections is quite a bit more complicated than making menu selections. An intelligent approach to selecting an appropriate developer involves understanding the developer's effects on factors such as: the type of film used; the kind of negative the combination will produce of a given subject; the printing method; the printing equipment; and the intended use of the resulting image. Happily, such criteria are not as complex as they sound, because for any specific kind of photography many of the possible options will be eliminated by obvious incompatibilities.
GENERAL-PURPOSE DEVELOPERS
All commonly available film developers can be placed in two broad classes: general-purpose developers and special-purpose developers. General-purpose developers are characterized by the fact that they display a well-balanced effect on all aspects of negative quality. They are formulated to provide what the manufacturer believes to be an ideal compromise in terms of their effect on apparent graininess, resolution, overall contrast, film speed and the characteristic response of the film. General-purpose developers are usually intended to develop all types of continuous-tone camera films equally well, including slow, medium and high-speed films. But this is not to say there aren't differences among the various general-purpose developers.
General-purpose developers can be further divided into two groups. High-energy developers are often best suited to large-format film sizes while relatively fine-grain, slower working developers are intended primarily for roll film sizes. Despite this differentiation, there's still a lot of crossover use.
High-energy developers like Acufine and Ilford Microphen, for instance, are very frequently used for small-format roll film developing to take advantage of the increase in effective film speed these preparations provide. And Agfa Rodinal is probably used more as a roll-film developer than as a large-format developer because of the very effective control of contrast in higher dilutions which it offers. On the other hand, large-format photographers often choose slower-working, general-purpose developers like Kodak D-76 or Edwal FG7 as a means of handling high-contrast subjects which would require shortening the development time of the more energetic types too much to exercise precise control.
ONE-SHOT OR NOT?
The form in which a developer is sold and used is quite important. Developers like Acu-1, Agfa Rodinal, Ethol Blue, Ilfosol 2, Nocco Sensidol and Unicolor B&W Film Developer are generally used as one-shot developers: they are concentrated preparations that are highly diluted to make a working solution that is meant to be used once and then discarded. Those one-shot developers that are sold as liquid concentrates have long shelf lives, making them particularly suitable to the infrequent use of many amateurs or subminiature film users who only need a little to develop a lot. They, are also very economical when used with developing tanks that require modest solution quantities for the amount of film being processed -- such as inversion-type tanks for roll film or film drums like those made by Unicolor which require even less developer to process each roll of film.
Some developers can be used undiluted and reused many times by maintaining their activity level through the addition of small amounts of replenisher solution for each roll of film developed. With the exception of Kodak HC-11O and Edwal Super 12, general-purpose developers which may be reused with replenishment are sold as dry powders that must be dissolved in water to make a stock solution. They include Acufine, Ethol 90, Ilford ID-11 Plus, Ilford Microphen, Kodak DK-50 and Kodak D-76. The shelf-life of any of these developers is limited, so reusing them with replenishment is only economical if they are used often to process moderate to large quantities of film.
WATERING IT DOWN
Many photographers convert some of these developers to one-shot use by diluting them 1:1 or 1:3 with water to make a working solution. This practice slightly alters a developer's characteristics compared to its normal performance. For instance, when you use either Ilford ID-11 Plus or Kodak D-76 in stock form, the high proportion of sodium sulfite tends to partially dissolve some of the silver in the film emulsion. This contributes to their fine-grain effect while at the same time limits the resolution of fine detail in an image. By diluting these developers for one-shot use the concentration of sodium sulfite is lowered, increasing image resolution at the cost of slightly more apparent graininess.
You should select a general-purpose developer if your subject matter and light conditions are varied and if you use more than one type of film. If, for instance, you use roll film and do not have a pressing need to obtain higher-than-rated film speed, choose from one of the slower-working, general-purpose developers. Your choices will be even narrower if you photograph only occasionally and develop in an inversion-type tank; a liquid-concentrate, one-shot developer would be more reliable and economical for you.
Your final selection should always be based an a practical test of each developer candidate. For each developer to be tested, expose a roll of film that specifically represents your usual range of subjects and conditions. Use the film's rated speed unless a higher E.I. is recommended in the developer instructions and bracket your test exposures on, above, and below the metered settings. Use the developer manufacturer's recommended developing time and temperature. If the resulting negatives are too flat or more contrasty than you would like, don't abandon the developer for that reason. Expose another test roll and adjust the film speed or development time -- up or down -- to obtain a desirable negative contrast. Then make comparison prints of your test negatives to determine which developer provides the image qualities that best suit you.
SPECIAL-PURPOSE DEVELOPERS
The same elimination and testing procedures apply to the selection of a special-purpose developer, but the key criteria differ. Rather than being formulated to provide a balanced compromise of negative qualities like general-purpose developers, those in the special-purpose classification provide their maximum performance in only one or two dimensions. This is accomplished by some sacrifice in the level of the other negative qualities affected by development. Thus a special-purpose developer should only be considered when the subject matter, lighting conditions and purpose of the photography are appropriate.
A photographer who specializes in candid, available light, submini people-pictures would be a good example. Although the order of importance of particular developer capabilities might differ, a photographer should choose a developer that provides a high film speed with fast films, good tone separation and gradation in the high and mid-tones, and moderate graininess. Soft lighting appropriate to portraiture limits the subject brightness range, eliminating the need for a developer that controls contrast. Nor does candid-portraiture demand recording the finest detail in the subject, so developers that maximize resolution can also be eliminated.
Special-purpose developers can be broken down into five basic groups:
1. Fine Grain.
Of all the special purpose types, fine grain developers most closely resemble general-purpose developers. The most popular versions have metol as the developing agent, along with a high proportion of sodium sulfite. Their fine-grain effect is attributed partly to the solvent effect of the sulfite and partly to their slow, soft-working characteristics. A common characteristic of all true fine-grain developers is that there is some loss of effective film speed compared to the more energetic general-purpose developers.
2. Acutance. These developers are formulated to enhance the appearance of sharp image resolution. This is accomplished by a phenomenon called "adjacency effect" which is achieved by utilizing the inhibiting effect on development of bromides that are the by-product of development. Most developers are formulated so the accumulation of bromides produced by the development process does not reach a level that would slow the overall effect of the developer. Acutance developers, on the other hand, allow the build-up of a concentration of bromides in the solution next to the emulsion. This build-up is significantly greater next to areas of heavy exposure (highlights) than it is next to areas of light exposure (shadows). Where light and dark tones are divided by a sharp line, the bromide concentration is diluted by the fresher developer adjacent to the shadow area. This causes the edges of the more exposed area to develop more density. Thus an enhanced difference in negative densities creates more apparent contrast between sharply defined light and dark tones in an image.
The adjacency effect of an acutance developer does not make an unsharp image sharp. It does increase the edge contrast between sharply resolved image details, improving definition and apparent sharpness of the image. The effect of an acutance developer relies on the fact that the film and developer are motionless for periods of time during processing. Therefore to ensure proper development only minimal agitation should be applied intermittently. The continuous agitation of a drum processor completely negates the adjacency effect and should not be used with an acutance developer.
You can obtain a mild adjacency effect to achieve some increase in acutance by diluting a fine-grain developer. Both Kodak Microdol-X and Ilford Perceptol may be used at a 1:3 ratio with water. Although some of the fine-grain qualities are lost with this rate of dilution, image resolution is improved by the reduction of the proportion of sodium sulfite and its solvent effect; some minor adjacency action is also incurred because of the weakness of the working solution.
3. Surface. Although the name implies a different kind of development action, commercially available surface developers actually function on the same principle as high dilutions of standard developers. A true surface developer would theoretically develop just the outer exposed surface of a film emulsion. Because it only requires part of the first minute of development for a solution to fully penetrate a film's emulsion and reach all the silver particles, real surface development would have to be completed in just a few seconds. Practically speaking, this would only be accomplished by a relatively high-speed, continuous-transport machine processor using a very potent developer solution sprayed on the emulsion surface.
Currently available surface developers are extremely potent liquid concentrates which you use in highly diluted form. The "surface effect" is achieved via the very diluted nature of the working solution. Almost immediately upon immersion in the developer some density is produced in all the exposed areas of the emulsion. As development progresses, density and contrast are built up at a progressively decreasing rate. This kind of development action which begins vigorously and tapers off produces higher than normal film speed, places a limit on the development of contrast, and holds apparent graininess to a moderate level. Because the effect of a surface developer varies according to the speed of the film being developed, different formulations for slow and fast films are offered.
4. Compensating. Compensating developers are distinguished by two special functions. To understand how they work we must be aware that compensation refers to the control of the development of negative contrast in direct relation to subject contrast. Mechanisms similar to those that produce acutance and surface effects provide the means to limit an excessive build-up of negative contrast. This compensating function depends on the local accumulation of development by-products in heavily exposed highlight areas or the rapid exhaustion of the solution adjacent to highlights. In this way the rate of development and density formation is inhibited in the highlights while the less exposed areas of the film develop more rapidly. Both functions may be incorporated to various degrees in compensating developer formulas.
Compensating developers are intended to allow you to make exposures of subjects of different contrast on a single roll of film and then get negatives that can be successfully printed using a normal range of paper contrast grades. Besides those developers that feature compensation as a primary function, some other developers like Edwal FG7, a general-purpose developer, are also mildly compensating. You can also achieve a moderate compensating effect by using higher dilution rates of some liquid-concentrate developers, notably Agfa Rodinal at 1:75 and 1:100.
5. Divided. Divided developers provide another way to achieve negative contrast control through compensation. These developers are so named because they are in two parts, usually designated A and B baths. Development is carried out by immersing the film first in developer bath A for a specified time and then immediately in bath B for another prescribed period. The primary ingredient in the first part of a divided developer is the developing agent which is absorbed by the film's emalsion. Little, if any, actual development takes place in bath A. The limited amount of developing agent carried over in the film emulsion to bath B is then activated by the very alkaline accelerator it contains. Development of the heavily exposed portions of the image rapidly exhaust the developing agent stored in the film emulsion limiting the maximum density of the highlights. The less exposed areas of the image exhaust the developing agent in the emulsion more slowly. This allows development to continue longer in the shadow areas.
Divided developers are economical because you can use them repeatedly without loss of activity even though they are not replenished. They control contrast effectively while usually providing on increase in the rated film speed. Moderately fine-grained results are achieved with some enhancment of image resolution. With some divided developers you can process different types of film in the same tank because the specified time in each bath is the same for some or all brands of general-purpose films. These advantages are balanced by the inconvenience of a more complex development procedure and the need to take extra care against contamination when using the chemicals.
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