From: Gerard NIEMETZKY (gerard@atxstudio.com)
Date: 06/12/00-07:51:03 AM Z
From: "Jeffrey D. Mathias" <jeffrey.d.mathias@worldnet.att.net>
Reply-To: alt-photo-process-l@sask.usask.ca
Date: Sun, 11 Jun 2000 18:00:22 -0400
To: alt-photo-process-l@sask.usask.ca
Subject: Re: Digital vs Analog - Corollary Questions
"The eye has a certain response to light, film has a certain response
which differs from the eye, and ink has another response different from
the others."
What are you talking about? Spectral response or densitometric response?
You are mixing two different
phenomenons in the following demonstration.
"..To test the transmission response of the ink do the following. Make
four gradients (and/or scan a 21-step) from 0% to 100% using only cyan,
magenta, yellow, and black. Print these with the DeskJet on
transparency film or cleared Tri-x film. Print these digital negatives
in Pt/Pd using an exposure that just gives maximum black to the uninked
substrate.."
What is the Max Density and the progressivity of each of these gradients on
the printed film?
You have to compare comparable things.
"You should find that the cyan gradient prints all black as the cyan ink
will not block much if any UV. The magenta gradient will have enough
maximum density to print a medium gray. The yellow gradient will have
enough maximum density to print a lighter gray. Only the black gradient
will have enough density to produce a white if enough ink is coming from
the printer."
You are showing there that your Pt/Pd emulsion does not have the same
sensitivity according to the quality of the light.
But to do so you must be sure that you expose with the same amount of light
i.e under the same densily (D=log(1/opacity))
for the different colors.
"...You should also find that a Zone I is obtained quite a
distance up the gradient meaning the a bulk amount of ink is used to
just get to Zone one. Now if you use the yellow ink to provide a
threshold for Zone 0, the resulting black ink to provide the rest of the
zones does indeed "look" flatter than an analog Tri-x negative. Think
of the yellow as base plus fog.
What does this all mean? Not a thing. It only maters how the negative
prints with a given process, not how it looks on its own.
-- Jeffrey D. Mathias http://home.att.net/~jeffrey.d.mathias/..."It means that every one should read the excellent book written by Dan Burkholder (Making Digital Negatives) There is no mistery there, only some rules to apply.
Gerard Niemetzky
This archive was generated by hypermail 2b29 : 07/14/00-09:46:45 AM Z CST