Re: what is a normal subject brightness range?

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From: Jeffrey D. Mathias (jeffrey.d.mathias@worldnet.att.net)
Date: 07/18/01-02:05:46 PM Z


Shannon Stoney wrote:
> When I was learning the zone system for silver printing, ...

The Zone System can be utilized for any process.

> ... But now, after reading Dick Arentz's book on pt/pd printing, I am wondering
> if my old method still holds for alt-process negatives.

Dick's method works for him, yours may differ, I know mine does.

> On another page he writes, "in calculating negative values with a
> transmission densitometer, both the useful highlight (Zone VIII) and the
> useful shadow densities (Zone III) are measured. After simple substraction,
> the difference is determined...this is the density range of the negative."

Again this is Dick's method. I base the useable density range of the
negative on the outcome of a print using the materials and process of
selection. The highest negative density that is used to print maximum
black and determine printing exposure is one end of the range and
determined first. The lowest negative density that results in no
exposure in the print (paper white) is the other end and determined
later. This is my method, but it is not finished.

Next, the speed point or Zone I is determined. This is the amount of
exposure to a certain film with a certain development that produces a
negative density just great enough to produce a decernable difference
from the maximum black, in the print when given the proper exposure.
This can be called film speed.

Next, each stop (or partial stop) of negative exposure is made and
printed (not to be confused with film speed, which remains constant
until development is changed).

Next (or simultaneously), each stop of development (N to N+1 is 1 stop
of development) is made and printed.

Next, each negative development and exposure is printed and evaluated.

Typically for a subject to be printed "full range", Zone I will be as
determined for the film speed; Zone V will include 18% gray; Zones III
and VII will retain full "texture detail" (local contrast); Zones II and
VIII will have the last bits of "texture detail" (local contrast); Zone
X or XI or XII or XIII will show paper white (no density, depending on
the process and materials used). For gelatin silver prints X is
typically white, whereas for 100% palladium prints XII and at times XIII
can typically be white.

> ... So, do you take this to mean that when metering a typical outdoor scene to
> determine if it is normal or not, one meters everything including the sky to
> see if it is seven stops; or does it mean that you only meter zones III
> through VIII? And if your meaningful highlights fall in zone VIII, it is a
> normal scene? (By my old system, it would be a N-1 scene.)

It means that you adjust your film speed and development for a
particular process with particular materials so as to produce the values
in the print corresponding to the values you meter. For a typical scene
(similar to what was used for calibrating above) metering and setting
Zones III and VIII should be sufficient. If the scene differs, the
metering of other Zones and making adjustments to place as desired in
the print may be required.

This answer is simplified, but a full procedure can be found in Chapter
3 of my guide (on-line from link at end).

And to finally answer your question of what is a normal subject
brightness range? It depends on what you define or set as "normal".
Someone might meter a rock as Zone V, VI, and VII and make the negative
to print it as Zone I to VI (what might be though of as increasing
contrast and shortening exposure), and further this may be their
"normal" way to photograph rocks.

As to the range of a negative, it is most important to determine the
negative densities as demanded from the selection of process and
materials and what is desired in the print.

-- 
Jeffrey D. Mathias
http://home.att.net/~jeffrey.d.mathias/


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