Datacolor User to User Support Group.

>Options being listed, and differing intents actually being used are not
necessarily the same thing. Printing conversions typically >offer differing
intents, other conversions often do not. 

 

It is true that the listing of options and the actual use of them are "not
necessarily" the same thing in Vista or anywhere else; but I suppose that
users have to have some faith in their being the same thing until proven
otherwise.  If there is evidence that they are not the same in Vista or any
other program, I think that the user has an obligation to report that to the
offending software producer so that they may correct it.  While printing
conversions do typically offer differing intents and other conversions do
not, I have to assume that when a dialog box offers the user the ability to
select intent as the Vista CM panel does the selection will govern those
conversions that can make use of it until proven otherwise.

 

>The default intent (which is seldom actually perceptual) is often put in
the perceptual slot, and used for all conversions if the >conversion is an
XYZ based conversion, instead of a Lab based one, in other words for source
profiles, instead of printer >profiles.

 

Not be argumentative, but I am not sure that I get your suggested meaning
here.  What do you mean by its not being "actually perceptual?"  What is
"actual perceptual" and is there a commonly accepted standard for defining
that?  Since specifically in the case of the Vista CM panel the intent
option consists of a drop down box that in my particular case includes not
only the various rendering intents found in Photoshop but some options that
map those rendering intents to the Microsoft WCS system, I have to wonder
why they would put a non-"perceptual rendering intent" in the perceptual
slot listed as being "perceptual."

 

Under the "Advanced" tab in the Vista "Color Management" panel, there is a
place that you can click on which will bring up a description of the panel
settings; it says:

 <mshelp://> mshelp:///I see a setting for  <mshelp://> "default rendering
intent" on the Advanced Tab in Color Management. What is rendering intent
and should I ever change its default setting?

A rendering intent determines how colors are represented when changing from
one device <mshelp://windows/?id=2af33251-a510-4f87-bd16-6b6e5fda2e04>  (and
consequently, color space) to another. You can think of rendering intent as
a style of rendering colors; it is the approach that Windows uses to choose
the right colors when displaying or printing.

If your program does not specify its own rendering intent, you can specify
the default rendering intent that's used. There are four common rendering
intents that cover the most common uses. Depending upon the rendering
intent, the appearance of a picture will be slightly different, since
Windows will use a different range of available colors to render it. These
are the four rendering intents in common use:


Rendering intent

Common use


Perceptual (photo images)

Best for photographic images. When colors are converted from one device's
color space to another, the relationship between colors is maintained.


Relative Colorimetric (line art)

Best when a few specific colors must be matched exactly, such as when
rendering logo graphics. This is also the best choice for the last
transformation stage in print previews. The colors that fall within the
allowable color space of both devices are left unchanged, but other colors
may change, resulting in compressed color tone. The relative colorimetric
rendering intent will map white from the source device color space to white
in the destination device color space.


Absolute Colorimetric (simulate paper)

Best for use in the last transformation stage when making page proofs where
you want to represent the paper color in the output. Absolute colorimetric
intent differs from relative colorimetric intent in that white in the source
color space is not mapped to white in the destination color space.


Saturation (charts and graphs)

Best for business graphics in which vividness is more important than
realistic color, such as with business charts and graphs. When colors are
converted from one device's color space to another, the relative hue is
maintained, but colors may shift.

Note

.         The Advanced tab also allows you to specify a mapping between WCS
gamut-mapping model profiles and the four common rendering intents. In
general, you should only change these rendering intent mappings if you have
installed third-party WCS plug-in gamut-mapping methods and you want to use
those instead of the default WCS gamut mapping. Most users will never need
to change these settings.

 

From the above and what I saw in the CM panel, I think that Vista does
distinguish between what settings refer to the traditional ICC profile based
CM system and their WSC system (which really has not been fully implemented
in Vista or other programs to date) and does make it clear that the
rendering intent refers to device profiles and not editting space or XYZ
profiles. However, I am not sure that it makes any real difference if the
devices MS refers to here are  source devices - if by that you mean input
devices - or output devices such as printer with a few notable exceptions.
The exceptions which I allude to are (a) that the rendering intent may only
be applied by the Vista CM system to printer profiles but not to other
device profiles and/or (b) that the rendering intent may be embedded into a
source device profile by Vista or, if already so embedded, read by Vista
when rendering the color space in other devices such as monitor displays,
printers, etc.   However, if you mean something different  from how I
construed it by the term "source profile" then I need some further
elaboration by you of what you are referring to.

 

> The Vista color control panel looks great, its a bit more difficult to
determine what it actually does

 

On this we are in agreement. J  This is especially true for the WCS
functions.

 

 

From: colorvision_group@yahoogroups.com
[mailto:colorvision_group@yahoogroups.com] On Behalf Of CDTobie@...
Sent: Thursday, August 14, 2008 9:26 AM
To: laurie@...; colorvision_group@yahoogroups.com
Subject: Re: [colorvision_group] High quality target for CD/DVD printing

 


In a message dated 8/14/08 12:26:50 AM, laurie@... writes:




>Windows Vista color management only considers perceptual rendering, despite
of all kind of settings combinations I have tried on >color management
panel.
 
I am not sure what has led you to this conclusion.  I opened up the Color
Management item in the Vista Control panel and saw that while perceptual was
the default rendering other rendering intents were available options.


Options being listed, and differing intents actually being used are not
necessarily the same thing. Printing conversions typically offer differing
intents, other conversions often do not. The default intent (which is seldom
actually perceptual) is often put in the perceptual slot, and used for all
conversions if the conversion is an XYZ based conversion, instead of a Lab
based one, in other words for source profiles, instead of printer profiles. 

The Vista color control panel looks great, its a bit more difficult to
determine what it actually does...

C. David Tobie
WW Product Technology Manager
Digital Imaging & Home Theater
Datacolor
CDTobie@...
www.datacolor.com/Spyder3


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