Re: Panther, sRGB, web browsers
Re: Panther, sRGB, web browsers
- Subject: Re: Panther, sRGB, web browsers
- From: Uli Zappe <email@hidden>
- Date: Mon, 15 Dec 2003 13:55:30 +0100
Am 15.12.2003 um 05:26 schrieb Chris Murphy:
OK clarification is due on my part. I'm referring to the the ColorSync
default settings for RGB, CMYK and Gray (found in System
Preferences>ColorSync in 10.0-10.2, and in ColorSync
Utility>Preferences in 10.3.).
Ah, I see.
But still, you also write:
The display profile is ignored by most applications, because most
applications assume monitor RGB so images they display are unmodified
by ColorSync.
Somehow I seem to misunderstand what you say here.
For test purposes, I have created an RGB test profile (with Display
Calibrator Assistant) that's "way off", so that you can easily see when
this profile is used. Now, when I switch to this profile (to be my
display profile) in the Displays System Preferences, *every* content of
my display changes color, be it from TextEdit, Preview, whatever - even
movies in DVDPlayer.
So obviously, this setting influences the displaying colors of every
app that's running, just as it should. And as far as I can see, that's
*all* a display profile should do - correct the display on this one
specific monitor I use. So where do we misunderstand?
Is this the reason for my current problem that changing the Color
LaserJet 5500's ColorSync profile in ColorSync Utility doesn't seem
to change printings from Preview, TextEdit and the like at all?
Maybe. I'm not that familiar with the LaserJet 5500's driver options
or what RIP it uses. It is a PostScript printer, correct?
ColorSync on OS X, when printing from apps that don't generate their
own PostScript, relies on the RIP doing PostScript color management.
It sends a source profile as a Color Space Array, but then expects the
printer's built-in RIP to supply the Color Rendering Dictionary. I'm
not sure how this has changed in Panther, but the UI as you are
describing it implies that setting a custom device profile should
cause Panther to include that as the CRD. That you continue to get the
same results regardless of this settings tells me that there is a good
chance Panther is either not generating a CRD (not sending a
destination profile to the RIP), or that it is but the RIP is ignoring
it.
Yes, the LaserJet 5500 (at least my configuration) is a network
PostScript printer. However, it seems to accept only RGB ColorSync
profiles:
The Factory Profile, according to ColorSync Utility > Devices, is
/Library/Printers/hp/Profiles/sRGB_A.icc
an HP supplied file that comes with Panther.
On its web site, HP also offers a specific CYMK ColorSync Profile for
the 5500, but Color Sync Utility wouldn't let me choose that as Current
Profile instead of the Factory Profile (it seems it only accepts RGB
profiles for the 5500!?!).
If I choose another RGB profile instead of the Factory Profile, nothing
happens. If this file isn't consulted, not used by the RIP or whatever,
I wonder why Apple/HP installed a ColorSync Factory Profile in the
first place.
That's the problem with depending on PostScript color management.
Each RIP does things differently, and I see PostScript color
management as a totally unreliable way of doing color management.
But as a consequence, that means that each app has to offer its own
color management settings for printing, correct? And that also means
that printing from apps that don't offer such a setting is guaranteed
to fail color-wise, right? Which would mean that even to print a simple
letter with the correct colors of e.g. a company logo on it requires a
layout application?
If this is really the way it is, frankly, coming to all this from the
outside, I'm shocked by the archaic state of affairs in the year 2003.
I thought color management is difficult because of the physics involved
and the software and hardware technologies necessary. Instead, much of
it seems to come down to a simple lack of standardization and
cooperation between apps, drivers and the OS. :-/
I think it a huge mistake to dump the selection of destination
profiles into a relatively obscure application instead of right in the
printer driver.
At least, ColorSync Utility can be opened directly from the Printer
Setup Utility's toolbar. This way it was very easy for me to find the
setting, otherwise I probably would not have found it.
But maybe the presence of a ColorSync option in every print dialog,
even if the print driver vendor didn't stick on in there, is an
indicator of this finally getting figured out.
At least if the GUI becomes a bit clearer. From what it says right now,
I just couldn't figure out which of the two settings I should use if I
wanted to apply system-wide color correction via the profile I choose
for the 5500 in the ColorSync Utility:
Color Conversion > Standard (the GUI says it uses the configured
ColorSync profile which is what I want...)
or:
Color Conversion > In Printer (the GUI says this setting creates colors
for PostScript printers which also seems to apply in my case...)
Part of my confusion is, of course, that there seem to be too many
things at once that don't work so in the end I got paranoid about
*where* the problems is...
Yeah, it's the sort of thing that makes me ask myself "hat mir jemand
ins Gehirn geschissen and vergessen umzur|hren? Verdammt Color
Management! Es macht mich ganz verr|ckt!" on a fairly regular basis.
;-)
Bye
Uli
________________________________________________________
Uli Zappe, Solmsstra_e 5, D-65189 Wiesbaden, Germany
http://www.ritual.org
Fon: +49-700-ULIZAPPE
Fax: +49-700-ZAPPEFAX
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| References: | |
| | >Re: Panther, sRGB, web browsers (From: Roger Breton <email@hidden>) |
| | >Re: Panther, sRGB, web browsers (From: Uli Zappe <email@hidden>) |
| | >Re: Panther, sRGB, web browsers (From: Chris Murphy <email@hidden>) |
| | >Re: Panther, sRGB, web browsers (From: Uli Zappe <email@hidden>) |
| | >Re: Panther, sRGB, web browsers (From: Chris Murphy <email@hidden>) |