I've attached a low res screen shot of the film family of curves part of the program. This section is used for analysis of the film curves. The data input section (not pictured) produces some of the basic information like fixed density and Delta-X film speed, a variation of CI, and Ilford's average gradient. In this section, you can investigate the individual curves in more detail. You can adjust the Subject Luminance Range, flare value, exposure placement, and density range.
There is a Zone value function. There's also an interesting function designed for use in commercial labs. Many photographers will snip a roll of film, judge the snip, and adjust the development for the balance. After choosing a density from the strip and what density you want the balance to be, this feature will extrapolate the development time required to achieve the target density.
One of the primary functions of the family of curves is the determination of development times. It will take the variables for desired negative density range, the subject luminance range considered average, and the average value of flare and extrapolate using the CI/Time and CI/EFI curves -3 to +3 development times for a given film. It also gives the film speed for each time in fixed density film speeds and Delta-X film speeds. It also uses three different ways to calculate the times - Fixed flare, variable flare, and a method I call the Practical flare model of development. It is a combination of the fixed and variable flare models which I believe better reflects the preferred film/paper matching that Jones saw in his tests.
The single curve in the attachment shows both the resulting density range from a 2.2 subject luminance range with no flare and the DR range feature (the red lines) which will indicate the subject luminance range required to produce the desired density range for that curve which in this example is 1.05.
There is section that does similar analysis with paper curves, and a section with a four quadrant reproduction curve that is in need of much work to get it working again.
There have been a number of good suggestions so far. Thank-you.