From: Carl Weese (cweese@earthlink.net)
Date: 06/20/03-03:29:27 PM Z
Mark,
A vacuum frame makes a significant difference in the overall look of a Pt/Pd
print: not just "sharpness" (which is an overrated standard) but the
increase in resolution from better contact enhances the smoothness of tone
that is a main reason for making direct contact prints.
I've yet to see a print from a digital negative that didn't show--not
"dots"--but an overall non-image texture, analagous to the grain you'd
expect to see in an enlargement of a few diameters, but without, to my eye,
the pleasing character of film grain in a good small format enlargement in
silver.
When contact printing with good contact, I've found that paper texture has
amazingly little effect. The slightest deviation from a perfectly smooth
surface destroys the resolution of a print made by enlargement, because
light scatter at the paper surface clobbers the projected image. But a
contact print on fairly rough surfaced paper can resolve surprisingly fine
image detail from the negative.---Carl
--
Web site with picture galleries
and workshop information
http://www.carlweese.com
From: Ender100@aol.com
Reply-To: alt-photo-process-l@sask.usask.ca
Date: Fri, 20 Jun 2003 16:21:16 -0400 (EDT)
To: alt-photo-process-l@sask.usask.ca
Subject: Variations in Density With Different Light Sources
Hi Folks,
Since things have been slow on the list lately, I figured that a few
questions might not choke the bandwidth here.
I am wondering if anyone has done any testing of variations of print density
with say PT/PD caused by different variables. I am doing a research
project with digital negatives and Photoshop curves for various processes
and have run into the issues listed below.
I'd appreciate any input anyone has and information on how much variance in
print density people have found due to these variables:
1. Hot spots in a light source.... either tubes, NUARC, Sunlight, etc.
I would assume Sunlight would be the least. I remember someone posting
that they found very little variance with tubes‹even when there was a fair
amount of space between the tubes. How much variance in log density?
2. Hand coating methods. Obviously you could get a lot of variation if
you used a floor mop. So I guess here the question would be better phrased
in the inverse. With an extremely good coating job, how close to zero
variance in log density can you get? .01 log density? .000001 log density?
Does anyone know the standards manufacturers use for silver gelatin paper?
3. I know folks use different methods for smashing the negative down on
the emulsion so it will print sharp‹such as printing frames with some sort
of pressure system, vacuum tables, plate glass and boulders, etc. Will a
loose negative affect density of the print at all, or just the sharpness of
the print?
4. Speaking of sharpness? I am sure different paper textures and
processes affect sharpness, but how sharp is sharp when printing even the
most sharp of alt processes? How small of a line or patter could one
expect to resolve in a print? One reason I ask this question, is that I
have heard people complain about the "dots" they get with digital negatives.
I have looked at a number of alt prints that don't come close to resolving
the dots of a digital negative‹either because of the process or the texture
of the paper.
thanks,
Mark Nelson
This archive was generated by hypermail 2.1.5 : 07/09/03-08:31:13 AM Z CST