Re: CMYK/RGB printing confusion - please help!
Re: CMYK/RGB printing confusion - please help!
- Subject: Re: CMYK/RGB printing confusion - please help!
- From: Chris Murphy <email@hidden>
- Date: Wed, 2 Mar 2005 17:03:07 -0700
On Mar 2, 2005, at 4:35 PM, Uli Zappe wrote:
E.g. Make a screenshot of a typical blue Aqua button, save it as TIFF,
open the TIFF in ColorSync Utility and apply a Quartz filter that
converts the (RGB) TIFF to the Apple supplied Generic CMYK. If you
check the "Preview" checkbox, the shining Aqua blue becomes dull.
Quartz filters are broken in more ways than I care to count today. I
really don't have the inclination to find out whether there is yet
another bug that explains this behavior. I don't use it or recommend it
because I don't trust it. I've spent enough time trying to reverse
engineer that godawful user interface to last me the rest of my life.
Ooops! :-( Is this also true for Cocoa apps in general, e.g. if I add
a CMYK image to TextEdit and then print from TextEdit (no Preview
involved)?
I haven't tested TextEdit to find out what it does. But how each Cocoa
application behaves is clearly not consistent, even when they're all
written by Apple.
On a side note, wouldn't that mean that you should always use
Monitor RGB as your working space? I mean, it's one conversion less,
and that's good, isn't it?
"working space" is an Adobe term for settings found in Adobe
applications. You can't set a working space for non-Adobe
applications.
Apple, in its "Color Management with Mac OS X Panther" documents (as
well as other ColorSync related documents), also uses the term,
without any reference to Adobe apps. On page 13, it recommends using
AppleScript to convert images to a working space.
A lot of people use the term incorrectly because the terminology policy
never came up with a good name for the kind of RGB color space that
came along with Photoshop 5, that divorced the image color space and
the display color space. I prefer to call it an editing space. Some
people like to call it a quasi-device-independent color space. But
because it first came about in Photoshop, and was only selectable as a
setting called an Working Spaces>RGB the term working spaces stuck to
the kind of well behaved profiles that isn't based on an actual device
(which wouldn't be well behaved). But Working Spaces is an Adobe term,
and it's a setting only found in Adobe applications, and it has very
specific meaning for those applications depending on the currently
selected color management policy. So to confuse it with something
totally different - i.e. an editing space, makes things confusing.
The reason I prefer the term editing space is because the reason we
have ProPhoto, Adobe RGB, ColorMatch RGB, etc. instead of Monitor RGB
is because it's the space we edit the image in before we output the
file.
Never tried it. Surprisingly enough Mail.app might be able to do this
:)
Then TextEdit should, too, shouldn't it?
I don't know. It would have to be tested.
If you take the CMYK target, and use the Embed Specific Profile
AppleScript to embed your canned CMYK profile into the image,
Which "canned profile" do you refer to?
The one HP supplied.
So, apart from the fact that *every* mode produces a blue that's more
or less too dark (and much too dark with every CMYK profile), the CLJ
5500 profile isn't as bad as I thought; maybe I can indeed get decent
color with a CMYK custom profile. Though I ask myself why each and
every CMYK profile (Apple's own Generic CMYK included) is so far off
with blue?!?
If you create blue in RGB, or an RGB variant, you will be disappointed
with the converted version more than 1/2 of the time. Blue is a very
difficult color to print unless you have blue ink in the printer (and
even then there is still plenty of room for improvement).
What I find totally strange, though, is that in "In Printer" mode - or
with Soft-Proof switched off in Preview (which is identical as far as
Preview is concerned) - there are such big differences, or any
differences at all, for that matter. If I open a TIFF in Preview, and
print from there into Preview again, why is there a difference?
Shouldn't this be exactly the same? It's the same image, displayed in
the same app, with color management explicitly switched off - why is
there a difference? This is a mess. :-(
Which is why most people don't give OS-level color management a whole
lot of credit, and why people such as myself have jobs. I'd like to do
more work to put myself out of business, because I really don't want to
be hassled with these same problems for eternity. It would be nice if
one day it actually worked even 1/2 as well as the marketing spin, and
after 10 years you'd think some noticeable progress would have been
made, but I see two steps forward and nineteen steps sideways and three
dosados.
Faster and easier than what? Jaguar perhaps? That was Mac OS X public
beta #2.
Very true ...
Remember a certain list I got a whole lot of flack on for saying that
at the time though?
That book, commissioned by Apple, laments the bypassing of ColorSync
by Adobe applications and yet that's the only way to get the best
possible results due to lack of black point compensation and
rendering intent selection in Apple's implementation.
Hm, you can specify rendering intents for Quartz filters in ColorSync
Utility.
a.) I have a ten foot pole restriction on Quartz filters.
b.) It's not an acceptable workaround for being unable to use them in
the print driver dialog itself.
Plus, the lack of an aforementioned Off switch so we can easily print
targets without an Adobe application.
EPSON were clever enough to include a "No color management" option in
their Print Panel options.
Which as I've illustrated before isn't really off. It's "Generic RGB" =
source, and "Generic RGB" = destination. Even though the source and the
destination are most certainly anything other than Generic RGB. But
since both are the same, there is a null transform. There's an explicit
off switch for untagged CMYK, and for apps that generate their own
PostScript which the OS can't touch.
Chris Murphy
Color Remedies (TM)
www.colorremedies.com/realworldcolor
-------------------------------------------------------------
Co-author "Real World Color Management, 2nd Edition"
Published by PeachPit Press (ISBN 0-321-26722-2)
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