Re: new to color management and have a few questions
Re: new to color management and have a few questions
- Subject: Re: new to color management and have a few questions
- From: Terry Wyse <email@hidden>
- Date: Fri, 24 Jan 2003 08:48:26 -0500
I'll take this one, I've got the time!
on 1/24/03 12:25 AM, mark andrew nassy wrote:
>
(1) is adobe rgb (1998) a device independent colorspace. are all rgb
>
color spaces device dependent? if adobe rgb is device dependent then
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how come equal quantities of rgb make gray in that color space?
All the standard Photoshop RGB Working Spaces are device independent and
"well-behaved" spaces. =R+G+B = gray in all RGB spaces (that I can think of)
that get installed with Photoshop.
Typically, the only RGB spaces that are NOT well-behaved in this manner are
custom scanner and digital camera input profiles.
>
(2) when i use color sync color management how is that different to
>
using another color management engine. different in this sense: if i
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embed a profile in an image is it the profile that is getting embedded
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or is colorsync embedding a pointer to a printer profile residing on my
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computer, for example. ie, if i open the file at home will it use the
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same profile i used in the office?
ColorSync is simply the underlying OS-level color management system on a
Mac. Although you can select the "engine" (CMM) in the ColorSync Control
Panel, the engine itself does not have to be ColorSync. With Photoshop for
example, you can override the OS CMM and use soemthing else like the Adobe
(ACE) CMM.
The profile itself is getting embedded in the image so the person receiving
the file does not even have to have that profile on their system. Mac/PC,
doesn't make any difference. And if you want, you can extract the embedded
profile and have it on your system.
>
what happens if someone with windows opens a file that has a colorsync
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profile embedded?
Well, strictly speaking it's an "ICC" profile which is cross platform. If
it's embbeded and they open it in Photoshop and their color management
policy is set to "Preserve Embedded Profiles", then it will just work as
long as they don't assign a different profile to the image later.
>
(3) how do i change the name of the profile in the photoshop color
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management menu? i purchased some profiles from profilecity.com but
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they do not use the names i want in that menu.
You'll need either a Profile Editor or something like Steve Upton's
ColorThink (www.chromix.com) tool to do this. There may be even a free Mac
util for this but I'm not sure.
>
(4) id like to create some profiles using profilecity.com for the
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overseas printers we use. however i know nothing of the process they
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use and it is unlikely i will be able to obtain the information. the
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graphic design department does not have any information that would be
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helpful either. we print on paper, wood, and cloth. any suggestions for
>
color managing such a process would be welcome.
Yikes! That's going to be tricky business. For the overseas printing, talk
to the printer and see if you can't use one of the standard Photoshop CMYK
"press" working spaces. There's several "US" spaces, a couple European ones
and a Japanese one.
For the wood and cloth printing, you're talking custom profiles here. If
you're new to this, consider hiring a color consultant for a couple of days
to work this out for you. Cost you a bit upfront but will probably save you
HOURS/DAYs of time in the end.
I once was asked to create profiles for iron-on t-shirt transfers. We
actually printed a profile target, transferred it to the t-shirt and
measured it! And it worked! I happen to use a Gretag Spectrolino/Spectroscan
which can tackle a job like this but not all spectros could do something
like this. Now when it came to profiling color that was to go on baseball
caps, I packed my gear and went home!
>
btw, the graphic designers do not send separations. i think we need
>
would need the ppd for the postscript printer they use overseas to be
>
able to do that, correct? and we dont have access to it).
Forget PPDs and printers, you need the press profile if it's going to be
printed on an offset press. Remember, you need the ICC profile of the final
"output" device; if that's a press, you need a press profile; if it's a
"printer", then you need to profile that.
>
currently the way color is handled is:
>
>
one graphic designer works in adobe rgb 1998 and and sends files
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overseas that way, or doesnt do any color management. all designers
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use coated pantone chips (i think for paper). i think it is used for
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all types of material we print on (paper, cardboard, wood, and cloth).
Not enough info to comment. Sounds like the designer is sending tagged RGB
images which they leave up to the overseas printer to separate to CMYK?
Might be OK but could be very dangerous if the printer is not clued-in to
ICC color management. And I always start with the assumption printers are
NOT.
>
im hoping to purchase the peachpit press book from bruce frazier on
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color management when it is available. hopefully it will help answer
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some of the questions my books and apples colorsync web site didnt
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resolve.
Me too. Just got the word from Amazon that mine is coming. Chris Murphy was
co-author by the way, a good color guy in his own right. Both are good guys.
I say that because I need them to sign my copy when I bump into them again!
Terry Wyse
--
__________________________________
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Color Management Consulting
v 704.843.0858
e email@hidden
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