Scaling The Negative for Printing

The basis of all black and white printing has to do with the negative. Well Duh. That part is generally understood. What is not generally understood is how the negative is shaped and controlled to the desired density range needed for different printing needs. Printing a silver gelatin print requires a negative with a density range between (Log E) .55 to .75 in densitometric terms. Those densities are for a projector enlarger using a condenser head or cold light head, respectively.

Two elements make up the density curve which creates the gradation of black (silver) from a deep rich black (DMax) at the lower end (toe) from paper base white at the upper end (shoulder). A fully scaled print. The shoulder & toe refers to the contrast index curve's density range of the negative, with the thickest densities at the top (shoulder) and the thinnest densities at the base of the curve (toe).

Contrast index curve seen as D Log E function;

The above scale has to do with time & density relationship, which every photographer who has developed negatives is familiar with. The general rule being that increased development time increases the densities of the negative. The more specific understanding of this rule being that this defines the densities above Zone 5. Once the tonal densities from Zone 1 through Zone 5 have been developed, no further amount of development will alter those densities. The tonal densities that will continue to develop begin around Zone 6, with each subsequent tonal density further increasing in density respectively. Understanding this relationship defines the ability to control these densities of the upper end of the scale by applying the expansion & compaction principle.

As the chart indicates, the two functions of the developing relationship are density and time, with density dependent on time. There is another element which alters this relationship. Developer dilution. The vast majority of photographers today use pre-packaged developers for negatives and prints; Kodak's D76 and Dektol. There are others, but these two are by far the biggest sellers. Here's the thing. One still needs to mix the pre-packaged chemicals to be used, and you are paying for the convenience of someone else actually mixing the chemicals before weighing them out and packaging them. That is no different than  using Bisquick to make your pancakes, when you can add the three dry ingredients yourself. We have become slaves to convenience, even when it is not in our best interest.

I know, I have written on this before. I would tell you that it is important for having full control over the development of the negative. The formula I wrote about was Beutler 105, a non M/Q developer, using only Metol as the reducing agent. I believe this to be probably the best general negative developing formula available. Formulas will come later. Next, though, is controlling the negative further through a compaction or expansion process, using time & dilution as the controlling functions.