Film development is endlessly fascinating to me, and led me to neglect printmaking in favor of negative making, in which the print is a proof of a negative, and any kind of manipulation obscures its purpose.
Making negatives begins at exposure and ends with a proof print, from which a fine print might be made.During exposure, creativity and technique are managed in real time as measured by discrete exposures. To the extent that conditions change over time, an exposure cannot be both discrete and identical. The only other real time event during the photographic process is film development. A discrete exposure can only be developed once, by an irreversible chemical process. After exposure, it is often suggested one should abandon creativity in favor of control, to secure the unique information latent in the undeveloped film. I don't consider creativity and control mutually exclusive.
Creative film processing takes all potential development controls into account to determine which combination of controls best serves the image. Film is necessarily chosen before exposure, and many or all of the processing choices might be made before, during or after exposure in anticipation of, or in reaction to exposure conditions . Controls vary in their influence and begin with the film/developer combination, which defines a set of conditions. Plain emulsion graphic arts film developed in a tray with print developer is going to make a different kind of negative than one made from the same film, developed in a dilute developer with reduced agitation. The influence a developer or development technique has on standard, panchromatic pictorial film is far more subtle than the example above, but its impact can be substantial.
Film developers are formulated to balance characteristics like emulsion speed, grain, sharpness and gradation, or to prioritize them. A good measure of a developer is that it maintains the balance of characteristics while enhancing the priority characteristic. Having a range of developers on hand allows for more creativity and more precise control.
Hypercat was formulated to produce high acutance while maintaining full emulsion speed, fine grain and excellent gradation. Despite being well balanced in characteristics, there is a price to pay for the sharpness of Hypercat; it is demanding of the processor. Unlike 510-Pyro or GSD-10, Hypercat is a two-solution developer and it is not suitable for rotary processing or significantly reduced agitation. Dilution and agitation are critical and must be determined by testing for desired effect. Inadequate agitation can result in streaks and other development defects, and excessive agitation results in a loss of film speed. In between the two extremes lie adjacency effects ranging from subtle to startling, available to those willing to commit the time and energy required of this developer. All that being said, the range of development times and agitation frequencies that give the best, most consistent results is in the normal range for standard developers; 6:00-10:00 minutes with ten seconds agitation per minute, but dilution and agitation frequency can be adjusted over a fairly wide range to suit desires and conditions.