Re: Ultrastable separations from Photoshop]

Charles Berger (cb@ultrastable.com)
Tue, 29 Jul 1997 08:24:18 -0700

>
> FotoDave@aol.com wrote:
> > >>
> >
> > How does one get the values for the printed densities? The file densities are
> > percent ink for CMYK (0 to 100) wherease if one measures the printed
> > densities using a densitometer, logarithmic densities (0 to about 2.1) are
> > obtained.

A Graphic Arts densitometer can give you direct percent dot readings
(transmission or reflectance). A densitometer that can only measure
optical, logarithmic densities can be used if the data is converted
into
percent Transmission and Reflection Values. This is also known as a
"Integrated Halftone Density to %" Table, where for example, a density
of 0.06 is equal to a Percent Dot Area of 13%. You can find these
tables
in several graphic arts publications and they will enable you to
calibrate for any printing system you choose.
Date: Mon, 28 Jul 1997 20:38:51 -0700
From: Charles Berger <cb@ultrastable.com>
Subject: Re: Ultrastable separations from Photoshop
To: FotoDave@aol.com
Cc: alt-photo-process-l@sasak.usask.ca
Message-id: <33DD65C8.160F@ultrastable.com>
Organization: ultrastable color systems,inc.
MIME-version: 1.0
X-Mailer: Mozilla 3.01 (Macintosh; U; PPC)
Content-type: text/plain; charset=us-ascii
Content-transfer-encoding: 7bit
References: <970729000157_1962503621@emout20.mail.aol.com>

FotoDave@aol.com wrote:
> >>
>
> How does one get the values for the printed densities? The file densities are
> percent ink for CMYK (0 to 100) wherease if one measures the printed
> densities using a densitometer, logarithmic densities (0 to about 2.1) are
> obtained.

A Graphic Arts densitometer can give you direct percent dot readings
(transmission or reflectance). A densitometer that can only measure
optical, logarithmic densities can be used if the data is converted into
percent Transmission and Reflection Values. This is also known as a
"Integrated Halftone Density to %" Table, where for example, a density
of 0.06 is equal to a Percent Dot Area of 13%. You can find these tables
in several graphic arts publications and they will enable you to
calibrate for any printing system you choose.