David: what is the proper way to make a contact sheet? Is there a standard exposure time? This is not something I usually do. I have been trying to *eyeball* them after the negatives are dry.
Yes, in a nutshell, here is the process (yell at me if it's unclear):
Set up your enlarger height to project white light to cover much more than 8x10 (to avoid light drop-off at the edges). Put paper down in the middle and lay your negatives in rows and cover with a sheet of glass (from a picture frame or whatever). Slide #2 contrast filter into the tray, set mid-aperture, and do the step wedge thingy across the whole area. You want 10 steps of 3 seconds (or whatever).
Develop. Look at the clear base of the film (rebate aka sprocket holes) and note the time (number of steps) it takes to get to black and won't get any blacker. That is your ideal exposure time for contact sheets for that film on that paper. Write that down. Ignore your pictures; it's the minimum time for maximum black through clear film base that we are after.
Make a straight contact sheet of that set of negatives. You should not be able (or only barely able) to distinguish the film from the sprocket holes. Lock or mark the head height and aperture. All of your contact sheets with that film brand and paper will be done from that aperture at that height for that time -- from now on. You won't be 'fiddling' to get a decent contact sheet.
You might notice a couple of things right away:
1) Your pictures are too dark to see. That means you are underexposing and your negatives are too thin.
2) Your pictures are too light -- no deep tones. That means you are overexposing and your negatives are too dense.
3) Exposure looks good but pictures are flat. That means you are underdeveloping.
4) Exposure looks good but pictures are really contrasty. That means you are overdeveloping.
5) Some combination.
Don't be at all surprised by 1 or 2. It's shocking but quite common. A 'maximum black film base' contact sheet has just told you the single most important thing in the world about how you take pictures.
If 3 or 4, you will need to fiddle with your development time, temperature, or dilution, but save that for later -- you can use contrast filters for now until you get exposure nailed.
I hope that is of some help. I know it sounds like a lot, but it isn't really, and if your contact sheets improve, it will make everything else SO much easier. For instance, when you go to print, once you have one print from a roll (aperture, time, filter), you can knock off all the others in the roll in rapid fire. You won't be jumping through hoops with each bloody frame.
When I took photography in college, we were briefly taught how to make contact sheets, but not why. Shameful, because it turns out that contact sheets are diagnostic tools! Once I made it standard practice, my exposure got better and my printing got a lot better.