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Re: Digital Negatives with enough Tones for Pt/Pd

FDanB@aol.com wrote:
> You needn't have density to provide pure white in the print when you are
> working with multiple negatives. ...

The method I am using is to print the three negatives at one time with
one exposure as a sandwich.  The densities of each negative simply add
together to form a new density value.  In this way the sandwich can be
considered to be a single negative.  The total number of tones is the
sum of the number of destiny steps of the three negatives.  And the sum
of the maximum densities should equal paper white.  Any more density is
wasted.  I do not wish to have too much density on the lower-mid or
highlight negatives, only enough to bring the sandwich to a particular
value.

What you say does make sense, if each negative is exposed separately. 
However, I have decided not to do it this way as I desire to make only
the one exposure.

I also want the lower-mid, highlight, and upper highlight values to be
controled separately in each coresponding negative.  For example, on the
highlight negative, any value below the Zone V-VI point (found on the
lower-mid negative) will be clear, and any value above the Zone VIII-IX
point (found on the upper highlight negative) will have the maximum
density that when added to the maximum density of the lower-mid negative
will produce the Zone VIII-IX value.

> ...In offset printing with duotones (or tritones, etc.), the midtones and
> lighter tones are produced, not by smaller dots of black ink, but by
> varying shades of gray ink. ...

The problem I have found with duotones or tritones (and Carl Fransman
had mentioned also trying duotones) is that even though greys are
produced, there are only 256 unique tones.  I am trying to produce more
than 256 tones in the negative that will be printed.  I have made some
256 step gradients and have played with this.  I always got less than
256 steps printed in the negative.  I am likely doing something
incorrect, but what.  Please let me know how you did it, if indeed you
have counted more than 256 unique tones in the result.  The only way I
have been able to get more than 256 unique tones is in the sandwich of
three negatives from THREE SCANS.

> When you overlap these values from two or more negative exposures, your
> tones increase.

In my case, I am overlapping negative densities, adding densities to
reduce the amount of light getting to the print.  This is different from
adding light to increase the amount of light getting to the print, even
though at times results can be similar.

But the point remains.  Even if two exposures are made from two
negatives, in the end only two unique exposures are given.  The
information in the negatives (produced only from 256 tones) cannot
produce more than 256 tones without manipulation.  Please send me an
example, if you've counted more.  Each tone may be adjusted to a new
value, but the total number of tones remains the same.  The negatives
may be manipulated in such a way so as to produce more tones, but this
manipulation has not come from the original scan.  The only way I have
found to get more tones is to make the multiple scans for portions of
the range (or increase the pixel depth).

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