Numbers can not quantify a feeling. . .
A fine photograph has A LOOK; A FEEL; A PRESENCE; there are qualities that cannot be measured or codified. They are seen and felt, yet have no tangible attributes. . . some things are impossible to put into words. You can run tests, plot curves, generate computer models, but the emotional response, if any, to a photograph is an experience and not a quantifiable known.
In the process of making the fine photograph there are subtle adjustments that the photographer literally pours into the image. These fine adjustments may actually not even be perceivable to the viewer, but they make or break the finished image.
In the creative process of making a finished print, there are no hard and fast rules. There are photographs that take on a completely different atmosphere than may have been seen or felt at the time the film was exposed. These are those “happy little accidents” as the painter Bob Ross would say. You may follow one direction you believe will make the image speak when in the field, which is totally abandoned in the darkroom at the time of printing. You make your best estimate as to what you believe you will eventually end up with, but you will not absolutely KNOW for sure what a film, paper, developer combination is really doing until you make a real photograph. It is all about that feeling. Do not allow yourself to get locked into any preconception. Allow your creativity to guide you. Do not get hung up on numbers or any hard and fast rules.
I keep coming back to the same point; you can not calculate feeling. There are some things that just exist and are not possible to be explained by a mathematical expression. . . they are emotional expressions. . . emotional responses. . . subject to any number of personal preferences of the individual. . . these preferences are the product of what make each person an individual. . . you cannot measure these things. . . they are subjective. Think about it. . . can art really be created and expressed by numbers???
Keep in mind that any hard rules or numbers are only a starting point. . . only a suggestion. Creativity comes from reaching far beyond hard figures and rules. The creative spark reveals the inner feeling by stirring the imagination with creativity.
JB