A common suggestion for a Zone I density is .10 above film base plus fog. A
common suggestion for Zone VIII density is 1.35 above film base plus fog.

Zone I is used for your film speed test. That remains constant regardless of
development time (within reason). Zone VIII is used for your normal
development time test. Once you have determined a Zone VIII time your N+1
time is the development time that moves a Zone VIII exposure to Zone IX
(about 1.55 above film base plus fog). Your N-1 time is the development time
that moves a Zone VIII exposure to Zone VII (about 1.10 above film base plus
fog). Your N+2 time is the time that moves your Zone VIII exposure to Zone X
(about 1.75 above film base plus fog). An N-2 time is the time that moves
Zone VIII to Zone VI (about 1.10 above film base plus fog). The other zone
densities above film base plus fog per Woods are Zone II .24, Zone III .35,
Zone IV .55, Zone V .75.

You don't necessarily have to make separate tests for each development time.
It's likely that in the course of making your normal development time test
you'll have negatives that equal or closely approximate at least some of the
plus and minus times. If so, you can just use them rather than exposing and
developing everything all over again for those times. For example, one of
the negatives from your normal time test may show a density of about 1.10
above film base plus fog. If so, use the time for that negative as your N -
1 time, etc. etc.

There are variations on all this, nothing is sacred and others may have
different suggestions or methods, which is fine. Whatever works etc. etc.

I actually stopped doing these tests myself a few years ago. If you do this
outdoors you'd be surprised how often the light changes from one exposure to
the next even under a clear sky. You have to constantly meter the corners
and the center of your target to make sure there are no light changes from
one exposure to the next or else the whole test is bad and you have to start
all over from the beginning. The last time I did it myself I went through a
box and a half of Agfa APX 100 film. For these and other reasons (e.g. I
hate testing) I now use The View Camea Store's zone system service to do the
testing using Phil Davis' system.

"~BitPump" wrote in message
...
Hello,

With a group of friends we are trying to calibrate our 4x5 systems for the
Zone System.
Could anybody please inform me about the densities of each zone for
different developments (N-3, N-2, N-1, N, N+1, N+2).
Preferably according to Woods.

After reading many books, brochures and web pages, we are currently more
than confused and would like an advice from somebody experienced.

With best regards,

Andrzej