Darkroom: Black & White Photographic Processing Chemistry

Despite the shrinking availability of black-and-white films and papers, the chemistry available that’s required to process black-and-white film and paper remains virtually untouched since the heyday of what we now refer to as “traditional” photographic processing. Of the remaining choices of black-and-white chemistry that has survived, some are optimized for commercial labs, while others are intended for home and school darkrooms. For practical reasons, we will only discuss the latter group below.

Film Chemistry

If you are discovering or returning to the wonderful world of chemical darkrooms, you’ll be pleased to know that almost all of the developers you knew and loved way back when are still available. Depending on the brand formula, some film developers can be replenished after developing an estimated number of rolls of film, while others cannot be replenished. The latter are referred to as one-shot developers.

From Kodak, we have liquid developers including HC-110 and T-Max Developer and RS Developer & Replenisher; and powdered developers including D-76 and Xtol, which is recognized for its ability to produce higher acutance than many other developing agents.

Acufine, a developer favored by photographers who like pushing the ISO ratings of black-and-white film and maintaining consistent shadow detail while keeping a moderate grain structure, is also still widely available, as is Diafine, which allows you to develop a variety of black-and-white film stocks simultaneously with a single developing time. ACU-1, a one-shot, non-replenishable film developer that’s also known for its ISO-pushing abilities, is still available. Other popular film developers still being manufactured include Tetenal Ultrafin Plus, Ilford’s ID-11, Ilfosol, Perceptol, Microphen and Ilfotec.

In addition to the above, B&H currently stocks film developers from Adox, Clayton,  Ecopro, Ethol, Foma, Heico, Photographer’s Formulary, Rollei/Agfa, Sprint System of Photography and ZONALPro.

Paper Chemistry

While most paper developers are essentially the same, they mostly differ from one another in the way they render tone (neutral, warm or cool), the types of papers they work best with, and the way they handle temperature and storage-length variations.

Kodak currently manufactures a choice of two black-and-white paper developers: Dektol, a powder-based developer that’s been a standard of the industry forever, and Polymax T, a popular liquid-based developer.

Ilford still maintains a rather full lineup of paper chemistry. Included among Ilford’s current offerings are Harman Warmtone Developer, Bromophen, Multigrade Developer and PQ Universal.

Other paper developers available through B&H include liquids and powders from Clayton, Ecopro, Edwal, Ethol, Foma, Fotospeed, Heico, Photographer’s Formulary, Solarol and Sprint Systems of Photography.

Replenisher

Developers become exhausted after developing “X” number of prints or rolls or sheets of film. In order to stretch the life of some, but not all developers, it’s usually possible to bring the developer back up to strength by adding replenisher to the tired developer.

Replenishers are available from Acufine, Ilford, Kodak and Photographer’s Formulary.

Stop Bath

Though plain water can be used as a stopover between the developer and fixer solution when processing black-and-white film and paper, many photographers and commercial labs prefer to use a stop-bath solution, which unlike a plain water bath, halts the developing process in its tracks. Because stop bath only requires a 30-second stopover between trays, as opposed to several minutes for plain water, the use of a stop-bath solution shortens the total processing time of the print or film significantly.

Most stop-bath solutions consist of a one or two-percent solution of acetic acid—called a working solution—which is fairly tame. But do be advised that undiluted acetic acid can be extremely harmful if inhaled. Another form of stop bath is called indicator stop bath, which contains a pH indicator (usually bromothymol violet), which turns the solution purple when it becomes exhausted, signaling that it’s time to mix a fresh batch. Stop-bath solutions also help to extend the life and potency of your fixer by eliminating any lingering developer solution from contaminating it.

Stop bath is available from a number of companies including Clayton, Ecopro, Edwal, Foma, Fotospeed, Ilford, Kodak, Lauder, Photographer’s Formulary, Sprint Systems of Photography and ZONALPro.

Fixer

One of the final steps in the black-and-white film and printing process is the fixer solution, which completely freezes the developing process and locks the image in place for decades of viewing enjoyment. Fixer is available in both powder and liquid form, as well as in a choice of standard formulation or rapid formulation for commercial labs and photographers with shorter attention spans. 

Another variance between types of fixers is whether or not they include a hardener.  A hardening fixer provides greater protection for your film and prints, but requires longer final wash times and makes manipulation and toning more difficult. A non-hardening fixer is recommended if you plan on toning your images once the development process is complete. Once your prints have been submerged in the fixer for the recommended time, the prints are removed in order to begin the washing process. Often, a hypo clear or fixer-remover bath precedes the final water wash, which helps to expedite rinsing times and further ensure a fully archival process. After the optional hypo-clearing step, prints or films are given the final water bath to remove all remaining traces of chemistry, and are then dried.

Fixer is available from Clayton, Ecopro, Edwal,Foma, Fotospeed, Heico, Ilford, Kodak, Lauder, Photographer’s Formulary and Tetenal.

Toner

One additional step many photographers add when printing black-and-white prints is toning, most commonly with either sepia (Berg, Foma, Fotospeed and Photographer’s Formulary)  or selenium toners (Berg, Fotospeed, Ilford and Kodak), which add a nice warm element to the photographic image. Besides sepia and selenium toners, there are also toners designed to cool the native neutral tone of the photographic image. In addition to altering the appearance of your image, toners—especially selenium—are used to provide protection and greater archival properties to your final print.