- Is your paper fresh? If not, acquire fresh paper.
- Is your paper developing chemistry fresh? If not, acquire fresh developer.
- As mentioned earlier, your paper and paper developer have a certain range that it's capable of, and how the print looks is a relationship between the paper/developer/print developing time, and what you do to expose and develop your negative.
- So, do a film exposure test, where you meter normally and shoot a typical static scene, but you bracket your exposures, say at EI 12, 25, and 50. Then develop it 'normal'.
- Now print all three brackets at Grade 2, to a point where you have good black (meaning shadows that appeal to you, how you like them to look). Do NOT worry about highlights at this point.
- Pick the exposure index you liked, say EI 25, and shoot an entire roll at that speed, metering normally, a static scene that is preferably the same as what you shot in the first part, in similar light.
- Now develop one third of this roll at a time, and print one of the negs. At 'normal' film dev time, do your highlights look like they have enough detail, or too much, or are they perfect? If the negative is too dense in the highlights and you can't get enough detail in the highlights, you need to shorten film development time, say 20%. If the highlights are dull and gray without beautiful variations of almost white, you need to increase film development time, about 20%. Now print the negs again.
- Continue doing this adjustment of film developing time until your negatives print with satisfying blacks and whites, and your mid-tones will be beautiful by default.
This really is the only way to get a feel for how you need to expose and develop your negatives so that they print well. Keep paper and chemistry fresh. Do not change paper or chemistry types at any time during this test, and do not be tempted to change from contrast grade 2. Keep all other things equal. The only thing that changes is how you expose and process film, and your paper enlarger exposure time will also change due to changing negative densities.
When you learn how to treat 'normal contrast and lighting' you will discover that low contrast scenes and high contrast scenes may require different treatment. You will also discover that no matter how consistent you try to be with film exposure and development, different negatives on the same roll of film will require changes in how you print them, and it's at this point you break out the other contrast grades, to compensate for these naturally occurring differences (or, if you simply want more or less contrast out of a scene than you had originally envisioned). It's good to get tuned into a mid grade as your 'target' or 'peg' (as Mark calls it), because then you have a lot of 'wiggle room' at the time of printing. If you're already at an extreme grade, like 0 or 5, if you need 'more' you are making it very difficult for yourself.
Just forget about curves, and go find out how to make your negative fit the qualities of the paper. That is all that really matters.