Digital BW, The Print

>On 02/11/2005 23:23:03, Steve Kale (stevekale@...) wrote:
 >PS:   PM 5 has a setting to allow the user to "define handling the gray
axis
>in the calculation of the perceptual rendering intent".  Unfortunately I
>don't have PM 5 and can't see from the online user manual what the options
>are. If anyone has info on this it would be appreciated.

From the PM5 Help File: 
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"Perceptual Rendering Intent Option

Daily work shows that different aspects are frequently required for ideal
implementation of a gray axis. ProfileMaker therefore provides two methods
for defining the gray axis. These definitions affect only the Perceptual
Rendering Intent. 

With Paper-Colored Gray, the substrate color of the scanner/camera testchart
or the paper color of the print run affects the entire color space. This may
shift the gray axis of the image. Colors in the image may end up with a cast
although they are in fact neutral. This means that even a medium gray still
has a yellow cast on a yellow paper. In printing, this corresponds to the
use of the same printing plates for papers with different colors (paper
white).

Note: From the technical point of view, this corresponds to relative
colorimetry with shadow compensation.

With the Neutral Gray option, the substrate color or paper color only
affects lighter areas. In the other color areas, the colors and gray axis of
the image are preserved to the best possible extent, and are not influenced
by the paper white.

Note: This corresponds to relative colorimetry in highlight areas and
absolute colorimetry with shadow compensation in the remaining colors.

Note: The default and recommended setting is Neutral Gray.

For example, if B/W and color images are positioned next to each other in
reproduction, the Paper Gray Axis option should be selected to achieve the
same impression in the neutral tones both in the B/W images and in the color
images. Conversely, if an ad is produced that must be reproduced with
identical results in offset printing and in gravure (with the exception of
highlights that are allowed to differ on account of the different papers
used), the Neutral Gray option should be used when generating the offset and
gravure profiles.

Note: The Perceptual Rendering Intent calculation options Paper Gray or
Neutral Gray don't affect the proofing process. In the proofing process the
Relative Colorimetric or Absolute Colorimetric Rendering Intent is used."
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TonyR