Black and white film processing and printing.

A Primer
by Isaac Crawford

        Despite all of the advances over the years in color films, black and white photography continues to play a pivotal role in creative photography. There are various reasons for this ranging from a cultish homage to Ansel Adams to an admiration of light and tones. Whatever the reason is, all photographers have to go through similar steps in order to achieve a monochrome image to their liking. This is an introduction to the various techniques that are used in order to create a monochrome image.
        It starts with the film. Traditional black and white films come in many different speeds and looks. The discriminating photographer will take the time to try various types of film. This way the photographer can pick the right emulsion for the right situation. The three primary attributes of film are the speed, how “grainy” they look, and their contrast. These three things are related and are all changeable by various development techniques.
        The film speed goes quite a bit beyond what the box says. All things being equal (and they never are), the faster (more sensitive to light) the film is, the more you notice the grain. So, a film that is ISO 400 will tend to show more grain than an ISO 125 film. Technological advances have thrown a bit of a wrench into the works. TMAX 100 is a relatively new film (it’s about 20 years old) and it exhibits less grain than an older ISO 50 film known as Panf+. So the lower ISO=lower grain is a rule of thumb only, not a hard and fast rule. In addition, the developer used can have a dramatic effect on the effective speed of the film. Tri-x Pan developed in D-76 is routinely rated at an EI (exposure index) of 200. On the other hand, an EI of 1250 is not uncommon when souping the same film in Dianfine.
        As an aside, many beginning photographers have a tendency to want to minimize grain, often times in the 35mm format. There are certainly reasons why you would want finer grain, but do not be afraid of grain. After all, the image is formed out of grain, so why try to hide it? There are certain films and developers that tend to minimize the appearance of grain, but it is always a matter compromise. Usually what is compromised is apparent sharpness. The best way to minimize grain is to use a larger film format. For any given enlargement size, the larger the negative, the lower the grain. Larger format cameras are available at very attractive prices these days on the used market. There are reasons not to use larger format cameras, but price really isn’t one of them any more.
        The contrast of the film is largely determined by the manufacturer. Some films are inherently contrasty, the recently discontinued Kodak Technical Pan f ilm is a prime example. It was originally designed to only give pure black or transparent areas on the film. This would translate to an image that is either black OR white with nothing in between. The contrast of the negative can be adjusted by how it is developed, though there are limits to this. Tech Pan (as it was called) could be made to approximate a “pictorial use” film by using a special super low contrast developer. Tweaking of the contrast is much more common than a wholesale change of film character. If one knows the “typical” contrast of a film, you can compensate when faced with unusually high or low subject contrast. This is best suited to large format photography where every single image can be processed on its own. Roll film users usually have to aim for a “normal” contrast when they develop their film because their images are likely to have various contrast ranges.
        After the film has been shot, it must be developed. Unlike color materials, there is no standardized black and white process. There are many choices of developer, dilution, time, etc. and all of them have an effect on the final result. There are, in typical use, 3 different types of chemicals used in processing black and white film. In order, they are the developer, the stop bath, and the fixer. Of these, the developer has the most impact on image quality and is the subject of most of the darkroom angst out there. The stop bath is an acidic solution that stops the development process immediately. This can be just about any acidic solution, lemon juice, vinegar, acetic acid, etc. Many people use water instead of an acidic solution. The water does not stop the developing action immediately, but many find that it does a good enough job that they can eliminate the stop bath. The fixer removes the unexposed silver and “fixes” the developed image so that it is no longer sensitive to light. One fixed, you may look at the negatives for the first time.
        The choice of which stop baths and which fixer to use is of no practical importance as far as the final image goes. The development is critical however, so this is where most of the effort goes in the darkroom. Each developer works in a slightly different way. Some (like Rodinal) will accentuate the edges of the grain to maximize apparent sharpness. Others (like Microdol-X) will try to “mush” the edges of the grain in order to minimize grainess, and still others are designed to boost film speed. The key is that different developers have different effects on the film and require different processing times, dilutions, and agitations. In order to get the best results, it is important to consider the exposure and development of the negative as the same step. The only way to know how to expose the film properly is to know the development ahead of time and the only way to know how to develop the film properly is by knowing how the film was exposed and what kind of subject contrast the photographer had to face. It is common for a roll film shooter to standardize on a particular developer for “normal” use but it is recommended to know how to process the film when faced with unusual circumstances such as really contrasty/flat subjects or subjects that require more or less apparent sharpness.
        The basic technique for exposing/developing black and white film is the same regardless of which combo of film and developer is chosen. It can be summed up by the adage, “Expose for the shadows and develop for the highlights”. The basic idea is that the density of the areas on the negative corresponding to the shadows are primarily determined by how much light hits the negative. In general, the shadow areas are not affected by subsequent development procedures, or at least not to the extant that the highlights are. The brightest areas in the picture will correspond to the darkest areas on the negative. How dense they are is directly related to the amount of development given to the film. The more the development, the denser (brighter on the print) the highlights become. Effectively, the shadows are set by the exposure and the contrast is determined by the development of the highlights.
        Once a developer is picked out, there are four factors that determine how much developing activity (and hence the contrast of the image) occurs. TIme, dilution, agitation, and temperature are the parameters that need to e looked into. TIme and dilution are fairly straightforward. The stronger the developer is, the more developing it can do. Likewise, the longer the film is in the developer, the more development that will take place. Heat is a catalyst in many chemical reactions, and ours is no different. The higher the temperature, the more development occurs. As the developer works, the active ingredients next to the film can become exhausted. Agitation of the film in the developer is used to replace the exhausted chemical with fresh. In general, the more agitation that is given, the more development that takes place.
        So how do you figure out the combination of time, dilution, temperature, and agitation that is required? There’s no need to panic, most manufacturers have tables of decent starting points for all of these variables. Keep in mind that they are only starting points, you must experiment to find the best combination for you. Most starting combos will be specified at 68 or 70 degrees Fahrenheit. Higher temperatures can usually be used if you shorten the time of development. If the time becomes too short, inconsistencies start to show up because there are fewer agitation cycles. A certain amount of time is required for the agitation patterns to “even out” given random fluctuations. Lower temperatures can also be used, but there is usually a point at which the developer looses all activity, so there is a lower limit to this. The classic standard for agitation in stainless steel tanks is 5 seconds of inversion for every 30 seconds of development time. This can be adjusted as needed.

        Once the negatives have been developed, prints must be made. Most people assume that there is but a single way of doing this. Indeed, the “silver gelatin projection print” has been the standard way of making prints from negatives for the past 50 to 60 years. There are other processes that were the “standard” before this, and they are making a bit of a comeback. Various non silver processes such as platinum and iron based processes (kallitype, cyanotype) have seen a resurgence of late. In addition, silver based alternatives such as contact printing, printing out materials, and albumen prints have also come back into vogue. Then there are the various photo processes that do not use metal based salts at all like carbon printing, chrysotype, gum dichromate, bromoil, and even photo engraving. All of these can be beautiful and I encourage you to give them a try.
        Alas, we will have to content ourselves with the “regular” materials. With projection printing, a negative is placed in a projector called an enlarger. This will allow us to pick the size of the enlargement we wish to have. Light is shined onto the paper and then it is developed. Proper exposure is usually determined by the use of “test strips”. A strip of paper is exposed at regular intervals of time, say 3 second steps. When the strip is developed, the best exposure is chosen and the entire image is exposed for that time. Enlarging paper is only sensitive to certain wavelengths of light, this is what allows us to use safelights. A frequency of light is picked that lays outside of the paper’s sensitivity and we can then see in the darkroom. With modern materials, an amber (officially OC filter) color is chosen instead of a red light. The human eye is much more sensitive to the amber than to the red, and this makes for a much more pleasant work environment. Please note that panchromatic black and white film (which is what normal B&W film is) is sensitive to ALL wavelengths of visible light. This means that you cannot use a safelight when developing film.
        In addition to choosing an overall exposure, the printer can choose to lighten and darken specific parts of the picture by allowing more light to hit the paper or by blocking light from parts of the paper. This process is called burning (making it darker) and dodging(making it lighter). In order to have a chance at doing these things well, the printer will usually try to have an overall exposure of at least 15 seconds. This gives the printer enough time to do the necessary dodging and burning to make the picture look they way they want.
        An even more dramatic control in printing is contrast adjustment. Most people are using variable contrast papers in the darkroom these days. With the use of filters, the printer can adjust the contrast of the print. There are several brands of filters out there, but they have 5 full grades of contrast and 6 half steps. The usual progression is from 00 to 5 in half grade increments. A #2 filter is usually deemed the “normal” contrast, anything higher than this results in more contrast, anything lower results in lower contrast. There is more “room” to go up as opposed to down, this is why if you are not sure how to develop the negative, it is better to lean to the lower contrast end of things. Much of the contrast can be put back in the printing process.
        The chemical process is the same as it is for film. You should use a developer designed for paper, but the same stop bath and fixer may be used. Unlike film, the differences between paper developers are relatively subtle. Also unlike film, most people use an acid stop bath in order to prolong the life of the fixer. After fixing (and usually washing), an image can be toned. Toning involves another chemical that interacts with the developed silver image, usually involving a color change. Toning can be done just for the color effect, and there is a whole rainbow of colors to choose from. Blue, green, brown, red, etc. Many people tone their images to improve the archival life of the print. Toners like gold, selenium, and sepia are often used for these purposes.
        There you have it. The whole process is really very simple and quite fun. There is also something very satisfying about making your own prints in a darkroom. If nothing else, developing your own B&W negatives will allow much better prints if done by someone else. Have fun!