ColorSync and printing -- Panther (1 of 2)
ColorSync and printing -- Panther (1 of 2)
- Subject: ColorSync and printing -- Panther (1 of 2)
- From: John Zimmerer <email@hidden>
- Date: Thu, 18 Dec 2003 18:32:15 -0800
Part 1 of 2
All,
I've been watching the thread on color managed printing unravel. Sorry
that I haven't had a chance to comment on this... I'm in the middle of
co-writing a white paper and a book on how ColorSync is integrated into
Mac OS X v10.3 "Panther". The white paper should be out around Macworld
(January). The book will be later in the year (2004). More on that
later.... My apologies in advance for the length of this post, but it's
a deep topic.
Here's the scoop:
1) ColorSync is ALWAYS ON in the printing system. There is always a
source profile, always a destination profile, and ColorSync is always
called to do something when printing, no matter what settings are made
in the driver. Sorry to "shout", but this needs to be understood at the
outset, so the rest of this makes sense. Please read this entire post
before flaming me.... <Grin>
2) You have a great deal of control* over how color is managed when
printing on Panther. You get to choose the source color spaces and the
output color space*. The caveat (*) comes into play below. Keep
reading....
3) Prior to Panther, all color printing done to PostScript
devices/queues used PostScript color matching, where all source data
was converted to CIE-based color, then matched in printer. This
required the printer to convert from the CIE-based source color spaces
in the PostScript to device color using the Color Rendering Dictionary
(CRD) in the (usually embedded) PostScript RIP. This proved to be less
than ideal, since many printers either a) provide poor (at best) CRDs,
and/or b) further manipulate the color, beyond simply matching it (they
assume most people want "punchy", not accurate color). It could also be
slooooooow, depending on the printer's processor. This, by the way, is
the exact same thing that selecting "PostScript color management" got
you in the LaserWriter 8 driver on Mac OS 9.
4) In Panther, we have supplied a new Print Dialog Extension (PDE),
called "ColorSync". This PDE is accessed by clicking on the pop-up
labeled "Copies & Pages" near the center of the Print dialog, and
scrolling down to "ColorSync". Find this now, it's your new best
friend. In Panther, when printing to PostScript devices, you have a
choice of using PostScript color management (called "In Printer"), or
host-based color matching using ColorSync (called "Standard"). "In
Printer" acts the same as earlier releases. "Standard" uses ColorSync
to convert from the source color in your documents to a single output
profile, and sends pre-matched device data to the printer/RIP. This is
the same as choosing "ColorSync color matching" in the LaserWriter 8
driver on Mac OS 9. Using "Standard" results in more accurate color as
there is no further manipulation by the device, and faster printing
since your printer isn't tasked with matching the color before
printing. Even if you're using a monochrome printer, you'll want to use
the "Standard" mode.
5) For raster devices, regardless of driver type (legacy "Tioga" or
CUPS), "Standard" (on-host) color matching is always used.
6) What defines source color? Well, that depends on whether the
application is using Quartz or if it does its own drawing/printing.
Most "pro" apps (e.g., Photoshop, InDesign, XPress) do their own
drawing/printing. Printing from these apps will be covered in the book,
not the white paper, since this falls outside of the design scope of
the "native" Quartz printing experience. For the most part, these apps
use either PostScript color management, or ICC-based color management.
For Quartz printing, there's a whole graphical chart I've worked up,
but since I can't email it to the list, it breaks down to this:
a) Source data tagged with ICC profiles is passed on (embedded in the
PDF spool file and used as source to be matched to destination when
printing).
b) Calibrated source color data are converted to ICC profiles, then
passed on as above.
c) Untagged, uncalibrated device data (DeviceGray, DeviceRGB,
DeviceCMYK) has the corresponding default ICC profile (Generic Gray
Profile.icc, Generic RGB Profile.icc, Generic CMYK Profile.icc)
assigned as source, and then is passed on as above.
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