Darkroom Tips: Fine Art of Developing Good Negatives. In one sense, the moment the camera shutter clicks the black and white picture has been made. Yet nothing shows on the black and white film: the black and white image is there but it is transient, reversed and invisible. Not until it has been brought out by development and then printed is the black and white picture there to be enjoyed. How enjoyable it will be depends to a great extent on how these steps are carried out. For they provide the photographer who processes his own black and white pictures with unparalleled opportunities to control the results. This control begins with the development of the negative. The techniques are simple, and using them to govern the quality of the black and white picture may mean nothing more than exercising care to get crisp detail and to keep off dust spots, stains and scratches. Control at the next level means adjusting the developing process to suit individual taste: for example, to produce especially fine grain in the black and white image so that a precise detail will show clearly in an enlargement, or to make black and white pictures a bit lighter or darker than average. Finally, control affords an opportunity, by the use of special chemicals and techniques, to salvage negatives that were wrongly exposed and to rectify mistakes in developing. At every level, such control aims to reproduce the original scene (or the black and white photographer's vision of it) by manipulating two basic characteristics of the negative: density and contrast. Density is simply the degree of darkness of the negative black and white image. It depends on the amount of black metallic silver in the black and white image. A dense, dark, negative is one that is generally heavy with silver (its opposite, a "thin" negative, has little silver and looks pale). The black and white image is formed by differences in density - the contrast between one tone and another. Density and contrast together build up the detail of an black and white image, and they determine whether it will be crisp or indistinct, grainy or smooth. A number of factors effect this black and white image-molding process. The developer itself, a complicated solution containing several chemicals, is the active molder of the black and white image. But equally important are the final steps of the process. The stop bath must apply a chemical brake to halt development quickly; the fixer must dissolve leftover emulsion crystals lest they too darken; and finally, clean water must wash away chemicals that might injure the black and white image. The actions of all these substances depend on their temperatures and on how long they are permitted to work on the black and white film - seemingly minor variations from recommended conditions have a strong influence on contrast and density. Time is easily controlled with timers. Temperature regulation requires more attention. All solutions must be kept at a standard temperature - usually 68° F. - by standing the bottles in a pan of 68° water. Even the tank or dish for developing black and white film is warmed or cooled as necessary before use, and in use it rests in a dish of 68° water.