From: Jeffrey D. Mathias (jeffrey.d.mathias@worldnet.att.net)
Date: 11/03/01-09:19:00 AM Z
Nick Makris wrote:
> ...
> Jeffrey, would you elaborate somewhat on what printing process you
> were referring to when you said:
>
> >What may be better would be to use a printing process
> >requiring less range or discrimination until a proper digital
> >negative can be produced.
Each process has unique characteristics that can distinguish it from
others. Many times it is valuable to take advantage of particular
characteristics by selecting a certain process.
Understanding that the bulk of my experience is with the Pt/Pd process
and to mention only a few of many processes for example: Processes like
Pt/Pd or carbon can utilize most of the information in a traditional
negative from film. They can deliver much more of any nuances the film
records, and (in general) require a carefully made negative with little
"wiggle room". Wiggle room being the ability to generate the best print
regardless of small changes in the making of the negative.
Silver gelatin typically allows for some "wiggle room" as it does not
require as much rigidity of requirements in the negative. For example a
slight over or under exposure can still produce equivalent prints as
long as the information for the print is in the "straight line" portion
of the negative (just giving more or less exposure). In this scenario,
Pt/Pd would loose highlights or shadows or overall separation from it's
ability. An adjustment is made so as to restrict the useable
information within a certain portion of the negative's ability (such as
a reduction in contrast, these negatives look "thinner" than those used
for Pt/Pd).
Xerography is one of the least information demanding processes. The
information for the best quality print can be stored in a small portion
of the negative's ability.
Now if the information in a negative is segmented into a certain number
of steps, it will be found that for a certain number of steps per change
in value that posterization will no longer be noticed. It is at this
point that a digital negative can "identically" (as can be discerned)
produce the results of a film negative.
For the processes mentioned above, it is likely that for Xerography
enough information can be stored in a digital negative. For gelatin
silver, it seems that the typical digital negative is slightly lacking
producing some noticeable posterization. This level of posterization
may be acceptable for some images of a "commercial graphic" nature but
fails to equal results using film. For Pt/Pd, the results are
posterized to such extent that many of the inherent uniqueness of this
process are lost.
The real test is to produce identical prints from both types of
negatives (digital and analog) while utilizing the entire ability of the
printing process. And consider also that different films can give
differnt results. For example, lith film may gives results closer to an
8-bit digital negative.
So not referring to any particular printing process, to obtain results
with a digital negative equivalent to those of a film negative, a
printing process requiring less range or discrimination should be
selected. If the unique attributes of a process are to be neglected,
then consideration should still be given to what attributes from another
process may be important. Yes, sometimes it may be best to print a
Xerographic print.
As digital technology improves, it may eventually rival or even surpass
a film like Tri-X. But that day is not today.
-- Jeffrey D. Mathias http://home.att.net/~jeffrey.d.mathias/
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