Re: shadow density in zone III highlight density in the erogenous zone

Sandy,

Good Points.

Not to take the thread off in another direction, but I would like to add one
other point. If you are planning on scanning your negatives, or use them for
both contact printing and scanning, then perhaps it is best to take into
account the capabilities of your scanner. Some scanners just don't do well with
really dense negatives. If you can get a good scan of the entire density
range of the negative, then you are in great shape—you can then match the density
range of the digital negative to just about whatever exposure scale you want
to use with the alternative process.

Another note on subject brightness range and shooting digital. It is common
to blow out the highlights with digital cameras. I have noticed with the
camera that I am currently using, by using a higher F-Stop and longer exposure
time I can compress a high subject brightness range to fit.

Best Wishes,
Mark Nelson
Purchase the eBook & PDN System for Your Own Custom Digital Negative Workflow
@
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www.MarkINelsonPhoto.com

In a message dated 9/29/05 11:02:24 AM, sanking@CLEMSON.EDU writes:

> The problem with just making denser negatives is that it is a
> generalization that makes no sense at all with many specific
> combinations of films and processes, and in fact this practice can
> have some negative consequences. It may make sense to overexpose with
> films that have very long toes because increasing exposure puts  more
> of the curve on the straight line part of the curve. On the other
> hand, films like TMAX-400 don't benefit at all from any increase in
> exposure because the curve is already almost perfectly straight line.
>
> Of course, some people deliberately over-expose on the rationale that
> it is better to have too much shadow density than too little.  But in
> answer to your question, yes, there is a definite down side to
> over-exposure in  that it limits the maximum average gradient, or
> contrast, of the negative, which can be a serious problem when
> working with low contrast type films with low contrast scenes. Films
> such as Tri-X and HP5+ are very definitely limited in their maximum
> potential contrast, and if you waste some of this at the bottom of
> the scale it can not be recuperated at the top with longer
> development times. Once a film is developed to its maximum CI, any
> further increase in time of development just gives denser negatives,
> not more contrasty ones.
>
> The Zone system is at best a very imprecise way of mapping
> subject-negative-print tones and the testing procedures can take a
> lot of time. If a person really wants to understand how to map these
> values with any specific combination of film and process they should,
> as Clay suggests, just bite the bullet and learn the language of
> sensitometry. BTZS is a very good system for mapping values, but in
> order to really use the system you need to have a basic knowledge of
> sensitometry.
>
> Sandy
>
Received on Thu Sep 29 15:29:31 2005