More than once when I was teaching photography I would ask a student, "What contrast is this printed at?" And usually there reply was, "I don't know." Because they would go into the darkroom and just start using an enlarger regardless of where it was set. Or they would print everything on 3. Not everything can be printed at the same contrast. Only the very best practitioners of the zone system, or guys who have been shooting a long time and have developed an intuitive sense about the exposure and development of their film are able to consistently hit a narrow range of contrast. For the rest of us, we have to find the contrast in the darkroom. What I will tell you about now is a working method, one that if learned and used will allow you to really begin to see contrast, and to judge that in the darkroom in order to produce prints that are more than mere representations of reality. Instead of using contrast to save a negative, you will use it for expression.
When you make your first test strip and print, you should do so at a very low contrast. I usually start around a grade 1, but I know that none of my prints ever come out that low. I don't nail it every time, but I haven't had a neg come out needing a low grade in a long long time. If you are not that confident, you might want to start on a 0. I would avoid the 00 or -1 as it is terribly flat and not much use. The reason you start low and work you way up is because prints look sharper and better if they are contrastier. Why not print them all very contrasty? Because the expression is usually better at a lower grade. If you print them too snappy, you will lose subtle details in the shadows that enhance the overall value of the print. If you want to see a very good demonstration of this. Print 2 prints, one on a grade 2, one on a grade 4. Show them to any non-photographer and ask them, "Which is sharper?" They will pick the 4. It's hard-wired into our heads, so don't think you can shortcut this process.
Make a test strip on a grade one. I usually use a full sheet but you don't have to. I like to because it gives me more things to evaluate. In my darkroom I have a viewing board which is a big cutting board standing up in a tray, and a 60 watt flood pointing directly at it. After the print is fixed I squeegie it onto the board and take a look at it. This next part is very important. Evaluate the test strip by only judging the highlights. Do not look at anything else. It will be very tempting to pick a strip by the middle tones or God forbid - the shadows. Don't do it! Look at the highlights. This will tell you the right exposure.
Now make a print using that exposure. Don't change anything!! Never change contrast and exposure at the same time. Ever. Even if you know it's the right thing to do, because then you confound the process by changing 2 variables at once, and most of the time you won't be able to tell which variable fixed the problem you were seeing. So you make a print. Now stick that under the viewing light and take a good stare at it. This is where we evaluate the contrast. Look at the blacks. Are they weak? It needs more contrast. Check the details that you want to show up in the shadows, are they there? If your blacks are inky, and you are missing a lot of shadow details, then you need less contrast. All of this assuming the details are there to begin with on the neg. If you've pushed or underexposed your film, this will still work, the process just won't be as much fun. Keep that in mind.
Now having made the determination of the contrast, you will have to make another test strip with the new contrast filtration in place. This is because the filter changes the amount of light available to the paper. Do not sidestep this. Just make another test strip, and evaluate the highlights only. Then make a print and check it out under the viewing light. Did the shadows get solid and strong looking? Good, then it is fine. Did you lose important details in the shadows? Too much contrast. Is it still weak looking? You need more contrast. Continue this process until you have a print that satisfies you.
You may be tempted when making that first adjustment to contrast to just crank it up a couple of grades. This is a very bad idea. Chances are you'll overshoot the mark and end up with an image that is too contrasty, but will look okay to you because you haven't seen it at the other grades, and you'll skip the rest of it and end up with mediocrity instead of greatness.
A few important things to remember. It is probably a good idea to mark on the back of the prints in soft lead pencil the exposure and contrast grade of each print right after you expose it but before developing it. This is important because you will probably end up with half a dozen prints and when it comes time to make final prints, you want to make sure you pick the right one.
Make sure your developer is fresh. Weak developer makes weak contrast. Be sure your safelights are safe!! A safelight that is fogging your paper is going to produce depressed highlights, and give you images an overall flat look, even if printed correctly.
Agitation of prints is very important. RC prints will almost develop themselves but fiber prints require some work. Ansel Adams, John Sexton, every great printer I know does not use tongs. Tongs are for ruining prints. They use their hands. I wear latex gloves to do this. The proper agitation for black and white fiber based prints is to flip them continuously. Face down - face up - face down etc etc. This will develop the print to completion and take another factor - incomplete development - out of the equation of fine printmaking.
Next we will work on the best way to determine where to dodge and burn. But that is another article!