Re: Digital Tones Needed for Pt/Pd Prints

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From: Jeffrey D. Mathias (jeffrey.d.mathias@worldnet.att.net)
Date: 05/08/00-06:17:04 AM Z


Stephen Harrison wrote:
> ... I have demonstrated at the last APIS conference in Sante Fe in 1999
> that my 7x17 inch digital images compare very favorably with my continuous
> tone digital images.

I do not recall seeing any image printed both from a digital and the
original negative.

> Recall my images taken in India of Tibetans living in
> exile which I photographed with a 7x17 inch Canham camera and can be viewed
> at www.talismanpress.com

Yes, these are great images and nice prints too.

> If you recall, they are all digital images
> scanned on a drum scanner with film made on an image setter and printed
> from the resulting digital negative.

What was the pixel depth used? My problem is that, I find that 8-bit
may not produce enough individual tones. And especially in the
highlights, it seems that there are even less gradations per change in
value that in the mid or shadow ranges.

How many individual gradations does your digital process produce? I
have been able to get 300 with photoshop, and it seems that all are able
to be printed. Again a problem is that the number of gradations per
zone (or sub-range of values) is less at the highlight end. What is
observed in the print is a merging of highlight values so that less
nuance of gradation and substance is found in the highlight areas.

> I defy anyone, independent of their
> level of photographic expertise, to tell which is the digital image and
> which is the continuous tone platinum/ palladium image. I will place them
> side by side and can guarantee that without a loupe, it is impossible to
> discern the digital imposter except to say that the test is unfair in that
> one may be subconsciously inclined to the digital because of the increased
> control and the life that can exist both in the shadow detail and
> highlights because of curves and that the " life breathed into the image"
> of which you speak is no problem in today's age.

First, I am not discussing nor concerned with digital impostors. My
interest is to manipulate (correct to my original seeing) the negative
to produce the desired print. Digital technique has many advantages
over analog technique, however there are some disadvantages to
overcome. The major pitfall at this time is the ability to produce
enough gradations in the negative (and finding out how many is enough?)

Without taking things personally, I would gladly take up the offer to
examine prints side by side to detect a difference. If there are not an
appropriate amount of individual tones, this can and will be detected.
A mater of looking for the right thing. If no difference is detected,
then it is important to know the number of gradations that you have
used, both overall and locally (as in a sub-range of highlights).

You are very correct that much can be added to the life of the image
using digital technique. However this may also hide this deficiency for
which I am trying to find a solution. It would be best to make a
digital negative that most closely resembles the original negative
rather than what should be used to make the print. In this manner Pt/Pd
prints from the negatives (original and digital) could be more fairly
compared.

> I will demonstrate this at
> the next APIS in Sante Fe with my Alaskan Landscape Series next year.

If we could do this before then, I would be most appreciative as I am
trying to accomplish this now. Also I may or nay not be at the next
APIS.

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


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