"~BitPump" wrote

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).

You don't need any standard OD numbers, nor a densitometer, nor a calibrated
tablet --
don't need much of anything really.

Start with taking pictures of a standard 18% grey card. The manufacturers ASA
rating
is a very good place to start - contrary to popular belief Kodak, Ilford and
Agfa _do_
know what they are doing. Adjust printing time so that when a print is made the
clear
film base produces a black of about 1.9 OD using your standard paper, enlarger
and
paper developer. Using this print exposure manipulate film development so the
18%
negative produces an 18% print. Any old grey card can be used, but once used it
is
now _the_ standard and all your metering, developing and printing is done
relative to this grey.

You don't want to go to DMAX for pure black or you will be too high up on the
shoulder
and detail will be lost in the deep blacks.

Make 1, 2 or 3 stops over or under exposed negatives of the same card for the
N+/-
tests.

Manipulate film development so that the under and over exposed negatives all
have
the same density as your 18% one.

You are done.

You may want to make step wedges. Make a series of N+/-x exposure &
development.
negatives that are -5 to +5 stops under/over exposed. Make standard prints of
the negatives
and cut and paste to make step wedge strips.

Using a 4x5, these tests can be sped up by making a set of dark slides with
holes in them
so that each dark slide exposes 1/4 (or whatever) of the film. Much the same
can be done
by inserting the dark slide a fixed amount while taking a series of exposures.

Using the step tablets you will be able to go directly from meter readings to
print tones.
This is the whole purpose of the zone system. And it really does work.

However, most people these days use 35mm cameras, standard exposure and
development
and graded/polycontrast paper. Same graded paper works just as well with 4x5.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
Remove spaces etc. to reply: n o lindan at net com dot com
psst.. want to buy an f-stop timer? nolindan.com/da/fstop/