There are even other approaches to determining correct exposure times. Noone has yet touched on measuring the light project onto the easel from the negative, for instance. This way, one can determine correct exposure for the hightlights, overall density range in the negative which would imply paper grade, density of assorted thin areas of the negative that may require dodging, etc. There are assorted tools to do this with, one of the least expensive is the Gossen Luna-Six meter with the baseboard attachment. I believe R&H sells something but it costs 10 times more than the Gossen meter. I've used this technique before, it works, it's fast and it saves a lot of paper. It won't give you the 'fine' ptinr the first time, but you'll get a good quality print the first time.
I would like to comment on the MTTMB approach. I've used it for years. At the beginning, I was using roll fillm and like most people I had to do a test strip for every negative in the roll that I wanted to print. This was because my densities were all over the place from one negative to another. When I learned of this technique, it made sense and I was interested in seeing what my negatives looked like. Well, I was very surprised by the contract prints that I got. I ended up making enlarged contract sheets in a 4x5 enlarger so I could study them closer. I was surprised at how underexposed they were almost uniformly. This was almost certainly due to me relying on the camera meter, which averaged a scene out. I invested in a handhel meter (eventually a spot meter) and things improved right away in terms of exposure. My instructor told me that a good density for highlights should barely let you read newsprint thru them which was the guidline I used until I really got into the Zone System. After the hand held meter and using newspaper to determine development times, my negatives started showing up a lot better on the MTTMB contact sheets. I got much more uniform negatives.
I still use this approach today and I think it makes a lot more sense with sheet film, where each sheet can be exposed and processed individually. To make a print from a 8x10 negative, I just expose it for the MTTMB time which I already know. The contact then shows all tones in relation to maximum black. If I made a mistake in exposure or development, it shows up light a neon sign. If a full-tone image, I will get a bright white area all the way down to one at or near paper black. Some prints may still require some dodging\burning, etc but this can be determined on an individual basis. For a long time, all my 4x5's could print an 8x10 with a standard print exposure time of 12 seconds, the minimum time to produce black thru the film edge.
I think the MTTMB approach can still be useful for roll film, especially as a check on exposures being too thin, but the lighting conditions for each individual image on a roll can vary so much that it's pretty difficult to get uniformity\consistency. Still, you may find that 75% of the exposures on a roll are all about the same and may therefore call for the same basic print exposure times, which is a good place to start.
So, BWGirl, if you're really starting out new at this here is what I'd suggest:
1) Go ahead and start with the test strip method. It will be something that you'll do no matter what refinements you may add in the future.
2) Give the MTTMB process a try. It will tell you LOT about your negatives and where you may need to improve exposure\development. I can't stress how important this is - if you're underexposing or over-exposing this technique, which is quite simple, will show it very quickly.
3) Lacking a densitometer, pay some negatives over newspaper in a sunlit room and see if you can just barely read the print thru the densest part of the negatives. If not, cut back development until you can. I know this seems odd, but it works. Later in lif, I tested this with expensive densitometers and it is actually true - this technique very cosely approximates the correct density to print a white on a grade 2 fiber paper.
Have fun.
-Mike