Don't take me too seriously, I'm poking fun at Bruce's enthusiasm as he makes his point that more exposure is a good thing.
When I look at my graphs, the straight line starts near my speed point (0.1 above Base+Fog).
Roughly mark the graph at 0.1 as Zone I. Mark a Zone on the graph for every other step wedge reading.
Suppose I follow Bruce and meter a dark part of my scene and place it on Zone IV. (Traditional Zone System would put on II - textured shadow). Now in my scene there would be a Zone darker (Traditional Zone I - featureless black). And a Zone darker still (Traditional Zone 0).
What I meant by my tongue in cheek comment was that Traditional Zone 0 (something two stops below my metered shadow) is going to be on the straight line portion.
The procedure you mentioned is just as described by Ansel Adams. However, I ask to myself, why should we define all the zones based on Zone I, when the reference exposure should be Zone V?
And I have another doubt concerning the concept of Zone V. How can the meter indicate the correct exposure to produce a middle gray print if the final result depends on developing and printing processes?
You could meter something gray, take the meter readings you get, and set them on the camera as-is. In Zone System language you "Placed" what you metered on Zone V. That's perfectly all right.
For black and white negative film... Shadows are where the film gets the least light. If you underexpose, the shadows get ruined because they get no detail on the negative. So almost everyone who uses Zone System meters shadows and places them so they get the right amount of noticeable detail.
Developing longer, such as N+2, will move light gray closer to white. And it will also move everything else a little. Like you suspect, it will move standard Zone V gray to a lighter gray. But since every tone moved in proportion this might look natural in the print - even though it is not faithful.
My question is how do I use the zone system with a handheld meter instead of the camera's built-in reflective meter? Thx!
I understand that, in practice, it's a good choice to take the shadows zones as references. However, when building the density x exposure graph, I thought that a more 'rigorous' approach would be adopted. I mean, I had thought the Zone V should be taken as reference because it is the one that may be compared to the standard middle gray card.
Zone System is meant to be used with a handheld meter! So just describe your meter or tell what model it is and someone here can tell you how to use it with the Zone System. Many of them work with a sticker that you can make yourself.
Spotmeters are best but if it is not a spotmeter, then you can walk right up to the thing you are metering and read very close to it (try not to put your shadow in the meter reading).
ps welcome erick and newtorf!
Two things you find out when doing black and white film testing: The film speed, and how long to develop.
Testing the shadow tells you the film speed. The "official" film speed tests use the shadow too. The meter relates film speed to gray Zone V.
Shadow detail doesn't change much when you develop more or less, so film speed test is a good test to do first.
When building the density x exposure graph, many of us use a 21-step Stouffer wedge, each step is a half f/stop. This gives plenty of information about everything from the shadow to the highlight. When done, you have a graph that tells you the density you get for the exposure.
There isn't a scientific way to match a paper to print on or to pick paper grade based on density of a negative. But developing your negatives so that they "fit" on a middle grade of paper gets you a negative that is possible to make a good print from.