Don't Play With Mud

Back in the days of film and B&W printing the way to control contrast was by paper grade. You'd be in your wet darkroom and have box after box of exactly the same paper (except for grade). Kodak did develop a variable grade paper at one point, but I never saw it used by the top quality photographers. It was the $49.00 photo editing package of its day. If the furthest you wanted to go was to develop your own B&W prints and give copies to family members, the variable grade papers were fine. If you wanted to do "fine art" work you'd invest in graded paper. Papers were available in six contrast grades, numbered from zero to five. Zero had the least contrast and you'd better have an extremely contrasty negative if you wanted to use that. Five was the other end of the scale and you'd have, what was called, a "soft" negative to use it. I don't know of any quality photographer who had all six grades stocked in the darkroom. Most would have grades two through four and that would serve about 99% of the need. Photographers knew how to expose a negative to fall somewhere in the mid-range of contrast. To listen (read) to a tirade about people printing muddy images today, hit the "read more".
Today, if you're using just about any of the popular photo editing software packages, including the freeware, you have some method of producing a B&W print. One of the key points photographers looked for in a wet darkroom on a B&W print was "a black black and a white white". Too many times today people doing B&W work have an image that starts out in the dark grey area and ends up in the light grey area. The result is a muddy print. Chances are extremely good that a linear contrast curve (a straight 45 degree line) isn't going to give a nice print with good contrast.

A typical contrast curve would look like a, "S" curve, with little movement toward the light and dark ends of the scale. You can also think of it as a bell curve distribution. (Don't try making a contrast curve look like a bell curve unless you're thinking about a solarized version of your print, complete with strong "mackie lines".) The bell curve is only useful as a tool for explanation. A bell curve looks like a bell. It's used to show "normal" distribution. It can be applied to just about anything. If you look at a bushel of apples, one will be the biggest and one will be the smallest. Most will be average sized. The distribution of sizes will be in the shape of a bell. Apply it to anything you can think of. People's intelligence? Someone is the smartest and someone is the dumbest. Most of us fit somewhere in the middle. Same thing goes for tones in a print. Something is the absolute blackest area of the print. Something is the absolute whitest area of the same print. The largest area of the print falls somewhere in between. A Kodalith image would be the exception, being only black and white with no grey scale.

What you'd want to look for in a B&W print would be a contrast curve (not the histogram bell curve) with a steep midsection. A steep midsection indicates higher contrast. You can't go nuts with it, but you want to avoid a bland 45 degree midsection. If you can get your print to have a "white white and a black black" and gooc contrast in the midtones you'll have a technically sound image. It might lack impact or composition, so a technically fine print doesn't automatically make it a "good" print, but a technically inferior print does guarantee a poor image.